diff --git a/.gitignore b/.gitignore
index 59509c753..ebb8912ce 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,7 @@ dhat-heap.json
 /docs/config/lua/keyassignment/CopyMode/index.md
 /docs/config/lua/mux-events/index.md
 /docs/config/lua/mux-window/index.md
+/docs/config/lua/MuxDomain/index.md
 /docs/config/lua/MuxTab/index.md
 /docs/config/lua/MuxPane/index.md
 /docs/config/lua/pane/index.md
diff --git a/ci/generate-docs.py b/ci/generate-docs.py
index 742e708e6..db47ec1d1 100644
--- a/ci/generate-docs.py
+++ b/ci/generate-docs.py
@@ -391,6 +391,7 @@ TOC = [
                     Gen("object: Color", "config/lua/color"),
                     Page("object: ExecDomain", "config/lua/ExecDomain.md"),
                     Page("object: LocalProcessInfo", "config/lua/LocalProcessInfo.md"),
+                    Gen("object: MuxDomain", "config/lua/MuxDomain"),
                     Gen("object: MuxWindow", "config/lua/mux-window"),
                     Gen("object: MuxTab", "config/lua/MuxTab"),
                     Page("object: PaneInformation", "config/lua/PaneInformation.md"),
diff --git a/docs/changelog.md b/docs/changelog.md
index 0fe5b4445..a4c05be1b 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -21,6 +21,10 @@ As features stabilize some brief notes about them will accumulate here.
   [#2741](https://github.com/wez/wezterm/issues/2741)
 * macOS: initial cut at macOS native menu bar
   [#1485](https://github.com/wez/wezterm/issues/1485)
+* mux: exposed [MuxDomain](config/lua/MuxDomain/index.md) to lua, along with
+  [wezterm.mux.get_domain()](config/lua/wezterm.mux/get_domain.md),
+  [wezterm.mux.all_domains()](config/lua/wezterm.mux/all_domains.md) and
+  [wezterm.mux.set_default_domain()](config/lua/wezterm.mux/set_default_domain.md).
 
 #### Fixed
 * X11: hanging or killing the IME could hang wezterm
diff --git a/docs/config/lua/MuxDomain/attach.md b/docs/config/lua/MuxDomain/attach.md
new file mode 100644
index 000000000..7d12ac2c8
--- /dev/null
+++ b/docs/config/lua/MuxDomain/attach.md
@@ -0,0 +1,17 @@
+# `domain:attach()`
+
+*Since: nightly builds only*
+
+Attempts to attach the domain.
+
+Attaching a domain will attempt to import the windows, tabs and panes from the
+remote system into those of the local GUI.
+
+Unlike the [AttachDomain](../keyassignment/AttachDomain.md) key assignment,
+calling `domain:attach()` will *not* implicitly spawn a new pane into the
+domain if the domain contains no panes. This is to provide flexibility when
+used in the [gui-startup](../gui-events/gui-startup.md) event.
+
+If the domain is already attached, calling this method again has no effect.
+
+See also: [domain:detach()](detach.md) and [domain:state()](state.md).
diff --git a/docs/config/lua/MuxDomain/detach.md b/docs/config/lua/MuxDomain/detach.md
new file mode 100644
index 000000000..9ef0beada
--- /dev/null
+++ b/docs/config/lua/MuxDomain/detach.md
@@ -0,0 +1,12 @@
+# `domain:detach()`
+
+*Since: nightly builds only*
+
+Attempts to detach the domain.
+
+Detaching a domain causes it to disconnect and remove its set of windows, tabs
+and panes from the local GUI. Detaching does not cause those panes to close; if
+or when you later attach to the domain, they'll still be there.
+
+Not every domain supports detaching, and will log an error to the error
+log/debug overlay.
diff --git a/docs/config/lua/MuxDomain/domain_id.md b/docs/config/lua/MuxDomain/domain_id.md
new file mode 100644
index 000000000..bda60976b
--- /dev/null
+++ b/docs/config/lua/MuxDomain/domain_id.md
@@ -0,0 +1,6 @@
+# `domain:domain_id()`
+
+*Since: nightly builds only*
+
+Returns the domain id.
+
diff --git a/docs/config/lua/MuxDomain/has_any_panes.md b/docs/config/lua/MuxDomain/has_any_panes.md
new file mode 100644
index 000000000..7ccdc8ea3
--- /dev/null
+++ b/docs/config/lua/MuxDomain/has_any_panes.md
@@ -0,0 +1,9 @@
+# `domain:has_any_panes()`
+
+*Since: nightly builds only*
+
+Returns `true` if the mux has any panes that belong to this domain.
+
+This can be useful when deciding whether to spawn additional panes after
+attaching to a domain.
+
diff --git a/docs/config/lua/MuxDomain/index.markdown b/docs/config/lua/MuxDomain/index.markdown
new file mode 100644
index 000000000..30ac84c99
--- /dev/null
+++ b/docs/config/lua/MuxDomain/index.markdown
@@ -0,0 +1,8 @@
+# MuxDomain
+
+*Since: nightly builds only*
+
+`MuxDomain` represents a domain that is managed by the multiplexer.
+
+It has the following methods:
+
diff --git a/docs/config/lua/MuxDomain/is_spawnable.md b/docs/config/lua/MuxDomain/is_spawnable.md
new file mode 100644
index 000000000..4051feb93
--- /dev/null
+++ b/docs/config/lua/MuxDomain/is_spawnable.md
@@ -0,0 +1,9 @@
+# `domain:is_spawnable()`
+
+*Since: nightly builds only*
+
+Returns `false` if this domain will never be able to spawn a new pane/tab/window, `true` otherwise.
+
+Serial ports are represented by a serial domain that is not spawnable.
+
+
diff --git a/docs/config/lua/MuxDomain/label.md b/docs/config/lua/MuxDomain/label.md
new file mode 100644
index 000000000..dc7b1910f
--- /dev/null
+++ b/docs/config/lua/MuxDomain/label.md
@@ -0,0 +1,9 @@
+# `domain:label()`
+
+*Since: nightly builds only*
+
+Computes a label describing the name and state of the domain.
+The label can change depending on the state of the domain.
+
+See also: [domain:name()](name.md).
+
diff --git a/docs/config/lua/MuxDomain/name.md b/docs/config/lua/MuxDomain/name.md
new file mode 100644
index 000000000..ee3b8b27e
--- /dev/null
+++ b/docs/config/lua/MuxDomain/name.md
@@ -0,0 +1,8 @@
+# `domain:name()`
+
+*Since: nightly builds only*
+
+Returns the name of the domain.  Domain names are unique; no two domains can
+have the same name, and the name is fixed for the lifetime of the domain.
+
+See also: [domain:label()](label.md).
diff --git a/docs/config/lua/MuxDomain/state.md b/docs/config/lua/MuxDomain/state.md
new file mode 100644
index 000000000..1e3b998ca
--- /dev/null
+++ b/docs/config/lua/MuxDomain/state.md
@@ -0,0 +1,10 @@
+# `domain:state()`
+
+*Since: nightly builds only*
+
+Returns whether the domain is attached or not.  The result is a string that is either:
+
+* `"Attached"` - the domain is attached
+* `"Detached"` - the domain is not attached
+
+See also: [domain:detach()](detach.md) and [domain:detach()](detach.md).
diff --git a/docs/config/lua/wezterm.mux/all_domains.md b/docs/config/lua/wezterm.mux/all_domains.md
new file mode 100644
index 000000000..cbd168d9a
--- /dev/null
+++ b/docs/config/lua/wezterm.mux/all_domains.md
@@ -0,0 +1,6 @@
+# `wezterm.mux.all_domains()`
+
+*Since: nightly builds only*
+
+Returns an array table holding all of the known
+[MuxDomain](../MuxDomain/index.md) objects.
diff --git a/docs/config/lua/wezterm.mux/get_domain.md b/docs/config/lua/wezterm.mux/get_domain.md
new file mode 100644
index 000000000..481035a80
--- /dev/null
+++ b/docs/config/lua/wezterm.mux/get_domain.md
@@ -0,0 +1,16 @@
+# `wezterm.mux.get_domain(name_or_id)`
+
+*Since: nightly builds only*
+
+Resolves `name_or_id` to a domain and returns a
+[MuxDomain](../MuxDomain/index.md) object representation of it.
+
+`name_or_id` can be:
+
+* A domain name string to resolve the domain by name
+* A domain id to resolve the domain by id
+* `nil` or omitted to return the current default domain
+* other lua types will generate a lua error
+
+If the name or id don't map to a valid domain, this function will return `nil`.
+
diff --git a/docs/config/lua/wezterm.mux/set_default_domain.md b/docs/config/lua/wezterm.mux/set_default_domain.md
new file mode 100644
index 000000000..46ae1353f
--- /dev/null
+++ b/docs/config/lua/wezterm.mux/set_default_domain.md
@@ -0,0 +1,10 @@
+# `wezterm.mux.set_default_domain(MuxDomain)`
+
+*Since: nightly builds only*
+
+Assign a new default domain in the mux.
+
+The domain that you assign here will override any configured
+[default_domain](../config/default_domain.md) or the implicit assignment of the
+default domain that may have happened as a result of starting wezterm via
+`wezterm connect` or `wezterm serial`.
diff --git a/lua-api-crates/mux/src/domain.rs b/lua-api-crates/mux/src/domain.rs
new file mode 100644
index 000000000..aa4283434
--- /dev/null
+++ b/lua-api-crates/mux/src/domain.rs
@@ -0,0 +1,83 @@
+use super::*;
+use mux::domain::{Domain, DomainId, DomainState};
+use std::sync::Arc;
+
+#[derive(Clone, Copy, Debug)]
+pub struct MuxDomain(pub DomainId);
+
+impl MuxDomain {
+    pub fn resolve<'a>(&self, mux: &'a Arc<Mux>) -> mlua::Result<Arc<dyn Domain>> {
+        mux.get_domain(self.0)
+            .ok_or_else(|| mlua::Error::external(format!("domain id {} not found in mux", self.0)))
+    }
+}
+
+impl UserData for MuxDomain {
+    fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+        methods.add_meta_method(mlua::MetaMethod::ToString, |_, this, _: ()| {
+            Ok(format!("MuxDomain(pane_id:{}, pid:{})", this.0, unsafe {
+                libc::getpid()
+            }))
+        });
+        methods.add_method("domain_id", |_, this, _: ()| Ok(this.0));
+
+        methods.add_method("is_spawnable", |_, this, _: ()| {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            Ok(domain.spawnable())
+        });
+
+        methods.add_async_method("attach", |_, this, window: Option<MuxWindow>| async move {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            domain.attach(window.map(|w| w.0)).await.map_err(|err| {
+                mlua::Error::external(format!(
+                    "failed to attach domain {}: {err:#}",
+                    domain.domain_name()
+                ))
+            })
+        });
+
+        methods.add_method("detach", |_, this, _: ()| {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            domain.detach().map_err(|err| {
+                mlua::Error::external(format!(
+                    "failed to detach domain {}: {err:#}",
+                    domain.domain_name()
+                ))
+            })
+        });
+
+        methods.add_method("state", |_, this, _: ()| {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            Ok(match domain.state() {
+                DomainState::Attached => "Attached",
+                DomainState::Detached => "Detached",
+            })
+        });
+
+        methods.add_method("name", |_, this, _: ()| {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            Ok(domain.domain_name().to_string())
+        });
+
+        methods.add_async_method("label", |_, this, _: ()| async move {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            Ok(domain.domain_label().await)
+        });
+
+        methods.add_method("has_any_panes", |_, this, _: ()| {
+            let mux = get_mux()?;
+            let domain = this.resolve(&mux)?;
+            let have_panes_in_domain = mux
+                .iter_panes()
+                .iter()
+                .any(|p| p.domain_id() == domain.domain_id());
+            Ok(have_panes_in_domain)
+        });
+    }
+}
diff --git a/lua-api-crates/mux/src/lib.rs b/lua-api-crates/mux/src/lib.rs
index 3af9a3fa1..f3daaa0b2 100644
--- a/lua-api-crates/mux/src/lib.rs
+++ b/lua-api-crates/mux/src/lib.rs
@@ -2,7 +2,7 @@ use config::keyassignment::SpawnTabDomain;
 use config::lua::mlua::{self, Lua, UserData, UserDataMethods, Value as LuaValue};
 use config::lua::{get_or_create_module, get_or_create_sub_module};
 use luahelper::impl_lua_conversion_dynamic;
-use mux::domain::SplitSource;
+use mux::domain::{DomainId, SplitSource};
 use mux::pane::{Pane, PaneId};
 use mux::tab::{SplitDirection, SplitRequest, SplitSize, Tab, TabId};
 use mux::window::{Window, WindowId};
@@ -13,10 +13,12 @@ use std::sync::Arc;
 use wezterm_dynamic::{FromDynamic, ToDynamic};
 use wezterm_term::TerminalSize;
 
+mod domain;
 mod pane;
 mod tab;
 mod window;
 
+pub use domain::MuxDomain;
 pub use pane::MuxPane;
 pub use tab::MuxTab;
 pub use window::MuxWindow;
@@ -107,6 +109,55 @@ pub fn register(lua: &Lua) -> anyhow::Result<()> {
         })?,
     )?;
 
+    mux_mod.set(
+        "get_domain",
+        lua.create_function(|_, domain: LuaValue| {
+            let mux = get_mux()?;
+            match domain {
+                LuaValue::Nil => Ok(Some(MuxDomain(mux.default_domain().domain_id()))),
+                LuaValue::String(s) => match s.to_str() {
+                    Ok(name) => Ok(mux
+                        .get_domain_by_name(name)
+                        .map(|dom| MuxDomain(dom.domain_id()))),
+                    Err(err) => Err(mlua::Error::external(format!(
+                        "invalid domain identifier passed to mux.get_domain: {err:#}"
+                    ))),
+                },
+                LuaValue::Integer(id) => match TryInto::<DomainId>::try_into(id) {
+                    Ok(id) => Ok(mux.get_domain(id).map(|dom| MuxDomain(dom.domain_id()))),
+                    Err(err) => Err(mlua::Error::external(format!(
+                        "invalid domain identifier passed to mux.get_domain: {err:#}"
+                    ))),
+                },
+                _ => Err(mlua::Error::external(
+                    "invalid domain identifier passed to mux.get_domain".to_string(),
+                )),
+            }
+        })?,
+    )?;
+
+    mux_mod.set(
+        "all_domains",
+        lua.create_function(|_, _: ()| {
+            let mux = get_mux()?;
+            Ok(mux
+                .iter_domains()
+                .into_iter()
+                .map(|dom| MuxDomain(dom.domain_id()))
+                .collect::<Vec<MuxDomain>>())
+        })?,
+    )?;
+
+    mux_mod.set(
+        "set_default_domain",
+        lua.create_function(|_, domain: MuxDomain| {
+            let mux = get_mux()?;
+            let domain = domain.resolve(&mux)?;
+            mux.set_default_domain(&domain);
+            Ok(())
+        })?,
+    )?;
+
     Ok(())
 }