diff --git a/macos/Sources/Features/Terminal/TerminalController.swift b/macos/Sources/Features/Terminal/TerminalController.swift
index 1aa2d0c6f..0d5aa5a9f 100644
--- a/macos/Sources/Features/Terminal/TerminalController.swift
+++ b/macos/Sources/Features/Terminal/TerminalController.swift
@@ -281,14 +281,15 @@ class TerminalController: NSWindowController, NSWindowDelegate,
         // If we have only a single surface (no splits) and that surface requested
         // an initial size then we set it here now.
         if case let .leaf(leaf) = surfaceTree {
-            if let initialSize = leaf.surface.initialSize {
+            if let initialSize = leaf.surface.initialSize,
+               let screen = window.screen ?? NSScreen.main {
                 // Setup our frame. We need to first subtract the views frame so that we can
                 // just get the chrome frame so that we only affect the surface view size.
                 var frame = window.frame
                 frame.size.width -= leaf.surface.frame.size.width
                 frame.size.height -= leaf.surface.frame.size.height
-                frame.size.width += initialSize.width
-                frame.size.height += initialSize.height
+                frame.size.width += min(initialSize.width, screen.frame.width)
+                frame.size.height += min(initialSize.height, screen.frame.height)
 
                 // We have no tabs and we are not a split, so set the initial size of the window.
                 window.setFrame(frame, display: true)
diff --git a/src/apprt/glfw.zig b/src/apprt/glfw.zig
index 89448c354..f38214e32 100644
--- a/src/apprt/glfw.zig
+++ b/src/apprt/glfw.zig
@@ -551,7 +551,16 @@ pub const Surface = struct {
     /// surface initialization time. This may be called before "self"
     /// is fully initialized.
     pub fn setInitialWindowSize(self: *const Surface, width: u32, height: u32) !void {
-        self.window.setSize(.{ .width = width, .height = height });
+        const monitor = self.window.getMonitor() orelse glfw.Monitor.getPrimary() orelse {
+            log.warn("window is not on a monitor, not setting initial size", .{});
+            return;
+        };
+
+        const workarea = monitor.getWorkarea();
+        self.window.setSize(.{
+            .width = @min(width, workarea.width),
+            .height = @min(height, workarea.height),
+        });
     }
 
     /// Set the cell size. Unused by GLFW.
diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 7961ea4a9..55d47defa 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -1066,11 +1066,15 @@ const Subprocess = struct {
         self.screen_size = screen_size;
 
         if (self.pty) |*pty| {
+            // It is theoretically possible for the grid or screen size to
+            // exceed u16, although the terminal in that case isn't very
+            // usable. This should be protected upstream but we still clamp
+            // in case there is a bad caller which has happened before.
             try pty.setSize(.{
-                .ws_row = @intCast(grid_size.rows),
-                .ws_col = @intCast(grid_size.columns),
-                .ws_xpixel = @intCast(screen_size.width),
-                .ws_ypixel = @intCast(screen_size.height),
+                .ws_row = std.math.cast(u16, grid_size.rows) orelse std.math.maxInt(u16),
+                .ws_col = std.math.cast(u16, grid_size.columns) orelse std.math.maxInt(u16),
+                .ws_xpixel = std.math.cast(u16, screen_size.width) orelse std.math.maxInt(u16),
+                .ws_ypixel = std.math.cast(u16, screen_size.height) orelse std.math.maxInt(u16),
             });
         }
     }