diff --git a/README.md b/README.md
index 0f52c6a..d44ca55 100644
--- a/README.md
+++ b/README.md
@@ -395,6 +395,14 @@ vim.g.neominimap = {
         enabled = true, ---@type boolean
     },
 
+    viewport = {
+        -- Highlight the visible source range on the minimap.
+        -- Only supported when layout == "float".
+        enabled = false, ---@type boolean
+        priority = 5, ---@type integer
+        hl_group = "NeominimapViewport", ---@type string
+    },
+
     --- Override the default window options
     ---@param opt vim.wo
     ---@param winid integer the window id of the source window, NOT the minimap window
@@ -989,6 +997,7 @@ Checkout the wiki page for more details. [wiki](https://github.com/Isrothy/neomi
 | `NeominimapCursorLineNr`   | To replace `CursorLineNr` in minimaps.     |
 | `NeominimapCursorLineSign` | To replace `CursorLineSign` in minimaps.   |
 | `NeominimapCursorLineFold` | To replace `CursorLineFold` in minimaps.   |
+| `NeominimapViewport`       | Visible source range overlay on the minimap. (float only) |
 
 ### Highlight Groups of Diagnostic Annotations
 
@@ -1086,11 +1095,10 @@ Checkout the wiki page for more details. [wiki](https://github.com/Isrothy/neomi
   Use [satellite.nvim](https://github.com/lewis6991/satellite.nvim),
   [nvim-scrollview](https://github.com/dstein64/nvim-scrollview)
   or other plugins.
-- Display screen bounds like
-  [codewindow.nvim](https://github.com/gorbit99/codewindow.nvim).
-  For performance, this plugin creates a minimap buffer for each buffer.
-  Since a screen bound is a windowwise thing,
-  it's not impossible to display them by highlights.
+- Display screen bounds in split layout.
+  Viewport overlay is supported in float layout.
+  For split layout, the minimap is shared across all windows in a tab,
+  making window-wise viewport display infeasible.
 
 ## Limitations
 
diff --git a/doc/neominimap.nvim.txt b/doc/neominimap.nvim.txt
index a4a1163..e72edfd 100644
--- a/doc/neominimap.nvim.txt
+++ b/doc/neominimap.nvim.txt
@@ -382,7 +382,15 @@ Default configuration ~
             -- Consider folds when rendering the minimap
             enabled = true, ---@type boolean
         },
-    
+
+        viewport = {
+            -- Highlight the visible source range on the minimap.
+            -- Only supported when layout == "float".
+            enabled = false, ---@type boolean
+            priority = 5, ---@type integer
+            hl_group = "NeominimapViewport", ---@type string
+        },
+
         --- Override the default window options
         ---@param opt vim.wo
         ---@param winid integer the window id of the source window, NOT the minimap window
@@ -927,6 +935,9 @@ HIGHLIGHT GROUPS OF NEOMINIMAP WINDOWS ~
   NeominimapCursorLineSign    To replace CursorLineSign in minimaps.
 
   NeominimapCursorLineFold    To replace CursorLineFold in minimaps.
+
+  NeominimapViewport          Visible source range overlay on the
+                              minimap. (float only)
   -----------------------------------------------------------------------
 
 HIGHLIGHT GROUPS OF DIAGNOSTIC ANNOTATIONS ~
@@ -1021,11 +1032,10 @@ NON-GOALS                               *neominimap.nvim-neominimap-non-goals*
     Use satellite.nvim <https://github.com/lewis6991/satellite.nvim>,
     nvim-scrollview <https://github.com/dstein64/nvim-scrollview>
     or other plugins.
-- Display screen bounds like
-    codewindow.nvim <https://github.com/gorbit99/codewindow.nvim>.
-    For performance, this plugin creates a minimap buffer for each buffer.
-    Since a screen bound is a windowwise thing,
-    it’s not impossible to display them by highlights.
+- Display screen bounds in split layout.
+    Viewport overlay is supported in float layout.
+    For split layout, the minimap is shared across all windows in a tab,
+    making window-wise viewport display infeasible.
 
 
 LIMITATIONS                           *neominimap.nvim-neominimap-limitations*
diff --git a/lua/neominimap/config/internal.lua b/lua/neominimap/config/internal.lua
index bfe7e63..a33d2e2 100644
--- a/lua/neominimap/config/internal.lua
+++ b/lua/neominimap/config/internal.lua
@@ -205,6 +205,12 @@ local M = {
         enabled = true, ---@type boolean
     },
 
+    viewport = {
+        enabled = false, ---@type boolean
+        priority = 5, ---@type integer
+        hl_group = "NeominimapViewport", ---@type string
+    },
+
     --- Override the default window options
     ---@param opt vim.wo
     ---@param winid integer the window id of the source window, NOT the minimap window
diff --git a/lua/neominimap/config/meta.lua b/lua/neominimap/config/meta.lua
index e3b28d3..600fa60 100644
--- a/lua/neominimap/config/meta.lua
+++ b/lua/neominimap/config/meta.lua
@@ -27,6 +27,7 @@ local M = {}
 ---@field search? Neominimap.SearchConfig
 ---@field mark? Neominimap.MarkConfig
 ---@field fold? Neominimap.FoldConfig
+---@field viewport? Neominimap.ViewportConfig
 ---@field winopt? fun(opt: vim.wo, winid: integer)
 ---@field bufopt? fun(opt: vim.bo, bufnr: integer)
 ---@field handler? Neominimap.Map.Handler[]
@@ -92,6 +93,11 @@ local M = {}
 ---@class (exact) Neominimap.FoldConfig
 ---@field enabled? boolean
 
+---@class (exact) Neominimap.ViewportConfig
+---@field enabled? boolean
+---@field priority? integer
+---@field hl_group? string
+
 ---@type Neominimap.UserConfig | fun():Neominimap.UserConfig | nil
 vim.g.neominimap = vim.g.neominimap
 
diff --git a/lua/neominimap/config/validator.lua b/lua/neominimap/config/validator.lua
index 350f85c..df8dd19 100644
--- a/lua/neominimap/config/validator.lua
+++ b/lua/neominimap/config/validator.lua
@@ -162,6 +162,11 @@ M.validate_config = function(cfg)
         fold = { cfg.fold, "table" },
         ["fold.enabled"] = { cfg.fold.enabled, "boolean" },
 
+        viewport = { cfg.viewport, "table" },
+        ["viewport.enabled"] = { cfg.viewport.enabled, "boolean" },
+        ["viewport.priority"] = { cfg.viewport.priority, "number" },
+        ["viewport.hl_group"] = { cfg.viewport.hl_group, "string" },
+
         winopt = { cfg.winopt, { "table", "function" } },
         bufopt = { cfg.bufopt, { "table", "function" } },
 
diff --git a/lua/neominimap/window/float/autocmds.lua b/lua/neominimap/window/float/autocmds.lua
index bd9b523..d34b692 100644
--- a/lua/neominimap/window/float/autocmds.lua
+++ b/lua/neominimap/window/float/autocmds.lua
@@ -46,12 +46,16 @@ M.on_win_closed = function(args)
         return
     end
     local window_map = require("neominimap.window.float.window_map")
-    if window_map.is_minimap_window(winid) and not config.float.persist then
-        logger.log.trace("This is a minimap window. Close minimap for current window")
-        local var = require("neominimap.variables")
-        local swinid = window_map.get_parent_winid(winid)
-        if swinid then
-            var.w[swinid].enabled = false
+    if window_map.is_minimap_window(winid) then
+        logger.log.trace("This is a minimap window. Clearing viewport for %d", winid)
+        require("neominimap.window.viewport").clear(winid)
+        if not config.float.persist then
+            logger.log.trace("Close minimap for current window")
+            local var = require("neominimap.variables")
+            local swinid = window_map.get_parent_winid(winid)
+            if swinid then
+                var.w[swinid].enabled = false
+            end
         end
     end
     vim.schedule(function()
@@ -149,9 +153,9 @@ M.on_minimap_buffer_text_changed = function(args)
     local win_list = require("neominimap.util").get_attached_window(bufnr)
     vim.schedule(function()
         for _, winid in ipairs(win_list) do
-            logger.log.trace("Resetting cursor line for window %d.", winid)
-            require("neominimap.window.float.internal").reset_mwindow_cursor_line(winid)
-            logger.log.trace("Cursor line reset for window %d.", winid)
+            logger.log.trace("Handling minimap buffer text change for window %d.", winid)
+            require("neominimap.window.float.internal").on_minimap_buffer_text_changed(winid)
+            logger.log.trace("Minimap buffer text change handled for window %d.", winid)
         end
     end)
 end
diff --git a/lua/neominimap/window/float/internal.lua b/lua/neominimap/window/float/internal.lua
index 7d2936f..4987aa8 100644
--- a/lua/neominimap/window/float/internal.lua
+++ b/lua/neominimap/window/float/internal.lua
@@ -184,6 +184,7 @@ M.close_minimap_window = function(winid)
     logger.log.trace("Attempting to close minimap for window %d", winid)
     if mwinid and api.nvim_win_is_valid(mwinid) then
         logger.log.trace("Deleting minimap window %d", mwinid)
+        require("neominimap.window.viewport").clear(mwinid)
         local util = require("neominimap.util")
         util.noautocmd(api.nvim_win_close)(mwinid, true)
         return mwinid
@@ -242,6 +243,8 @@ M.refresh_minimap_window = function(winid)
 
     M.reset_mwindow_cursor_line(winid)
 
+    require("neominimap.window.viewport").refresh(winid, mwinid)
+
     logger.log.trace("Minimap for window %d refreshed", winid)
     return mwinid
 end
@@ -296,6 +299,23 @@ M.reset_mwindow_cursor_line = function(winid)
     return true
 end
 
+--- Called when minimap buffer text is updated.
+--- Refreshes cursor line and viewport overlay without reconfiguring the window.
+---@param winid integer
+M.on_minimap_buffer_text_changed = function(winid)
+    local logger = require("neominimap.logger")
+    local window_map = require("neominimap.window.float.window_map")
+    logger.log.trace("Handling minimap buffer text change for window %d", winid)
+    local mwinid = window_map.get_minimap_winid(winid)
+    if not mwinid or not api.nvim_win_is_valid(mwinid) then
+        logger.log.trace("Minimap window is not valid for %d", winid)
+        return
+    end
+    require("neominimap.window.util").sync_to_source(winid, mwinid)
+    require("neominimap.window.viewport").refresh(winid, mwinid)
+    logger.log.trace("Minimap buffer text change handled for window %d", winid)
+end
+
 ---@param mwinid integer
 ---@return boolean
 M.reset_parent_window_cursor_line = function(mwinid)
diff --git a/lua/neominimap/window/init.lua b/lua/neominimap/window/init.lua
index 3d1c2a6..8b5e444 100644
--- a/lua/neominimap/window/init.lua
+++ b/lua/neominimap/window/init.lua
@@ -8,6 +8,7 @@ api.nvim_set_hl(0, "NeominimapCursorLine", { link = "CursorLine", default = true
 api.nvim_set_hl(0, "NeominimapCursorLineSign", { link = "CursorLineSign", default = true })
 api.nvim_set_hl(0, "NeominimapCursorLineNr", { link = "CursorLineSign", default = true })
 api.nvim_set_hl(0, "NeominimapCursorLineFold", { link = "CursorLineSign", default = true })
+api.nvim_set_hl(0, "NeominimapViewport", { link = "Visual", default = true })
 
 ---@class Neominimap.Window
 ---@field create_autocmds fun(group: string | integer)
diff --git a/lua/neominimap/window/viewport.lua b/lua/neominimap/window/viewport.lua
new file mode 100644
index 0000000..26af764
--- /dev/null
+++ b/lua/neominimap/window/viewport.lua
@@ -0,0 +1,102 @@
+local M = {}
+local api = vim.api
+local config = require("neominimap.config")
+local coord = require("neominimap.map.coord")
+local fold = require("neominimap.map.fold")
+local logger = require("neominimap.logger")
+
+---@class Neominimap.Viewport.Cache
+---@field w0 integer
+---@field w_dollar integer
+---@field sbufnr integer
+---@field mbufnr integer
+---@field line_count integer
+
+---@type table<integer, Neominimap.Viewport.Cache>
+local cache = {}
+
+---@type table<integer, integer>
+local match_id_map = {}
+
+---@param swinid integer
+---@param mwinid integer
+M.refresh = function(swinid, mwinid)
+    if not config.viewport.enabled then
+        return
+    end
+    if not api.nvim_win_is_valid(swinid) or not api.nvim_win_is_valid(mwinid) then
+        return
+    end
+
+    local mbufnr = api.nvim_win_get_buf(mwinid)
+    if not mbufnr or not api.nvim_buf_is_valid(mbufnr) then
+        return
+    end
+
+    local sbufnr = api.nvim_win_get_buf(swinid)
+    if not sbufnr or not api.nvim_buf_is_valid(sbufnr) then
+        return
+    end
+
+    local w0 = vim.fn.line("w0", swinid)
+    local w_dollar = vim.fn.line("w$", swinid)
+    if w0 == 0 or w_dollar == 0 then
+        return
+    end
+
+    local cached_folds = fold.get_cached_folds(sbufnr) or {}
+    local start_row, end_row = fold.get_visible_range(cached_folds, w0, w_dollar)
+    local m_start_row = coord.codepoint_to_mcodepoint(start_row, 1)
+    local m_end_row = coord.codepoint_to_mcodepoint(end_row, 1)
+    local line_count = api.nvim_buf_line_count(mbufnr)
+
+    local cached = cache[mwinid]
+    if
+        cached
+        and cached.w0 == w0
+        and cached.w_dollar == w_dollar
+        and cached.sbufnr == sbufnr
+        and cached.mbufnr == mbufnr
+        and cached.line_count == line_count
+    then
+        return
+    end
+
+    logger.log.trace("Refreshing viewport overlay for minimap window %d", mwinid)
+
+    local old_match_id = match_id_map[mwinid]
+    if old_match_id then
+        pcall(vim.fn.matchdelete, old_match_id, mwinid)
+    end
+
+    if m_start_row > line_count then
+        cache[mwinid] = { w0 = w0, w_dollar = w_dollar, sbufnr = sbufnr, mbufnr = mbufnr, line_count = line_count }
+        logger.log.trace("Viewport overlay cleared (out of range) for minimap window %d", mwinid)
+        return
+    end
+
+    local end_line = math.min(m_end_row, line_count)
+    local pattern = string.format([[\m\%%>%dl\%%<%dl.*]], m_start_row - 1, end_line + 1)
+    local ok, match_id =
+        pcall(vim.fn.matchadd, config.viewport.hl_group, pattern, config.viewport.priority, -1, { window = mwinid })
+    if ok and match_id ~= -1 then
+        match_id_map[mwinid] = match_id
+    else
+        logger.log.warn("Failed to add viewport match for window %d: %s", mwinid, tostring(match_id))
+    end
+
+    cache[mwinid] = { w0 = w0, w_dollar = w_dollar, sbufnr = sbufnr, mbufnr = mbufnr, line_count = line_count }
+    logger.log.trace("Viewport overlay refreshed for minimap window %d", mwinid)
+end
+
+---@param mwinid integer
+M.clear = function(mwinid)
+    local match_id = match_id_map[mwinid]
+    if match_id then
+        pcall(vim.fn.matchdelete, match_id, mwinid)
+    end
+    match_id_map[mwinid] = nil
+    cache[mwinid] = nil
+end
+
+return M