---
title: "useMount – Effect Hook Usage & Examples"
description: "React lifecycle hook that executes a function after the component is mounted."
canonical: https://reactuse.com/effect/usemount/
---

# useMount

React lifecycle hook that executes a function after the component is mounted

`useMount` runs a callback exactly once after the component mounts, equivalent to `useEffect(() => { ... }, [])`. It provides a semantically clear way to express mount-only logic without manually specifying an empty dependency array. The callback receives no arguments and does not support a return-based cleanup function.

### When to Use

- Running one-time initialization logic such as analytics tracking, logging, or third-party SDK setup
- Performing DOM measurements or imperative focus calls immediately after the component first renders
- Replacing class component `componentDidMount` behavior with a concise hook

### Notes

- **No cleanup**: `useMount` does not support a cleanup return value. If you need unmount cleanup, pair it with `useUnmount` or use `useEffect` directly.
- **Development validation**: In development mode, a console error is logged if the provided argument is not a function.
- See also `useUnmount` for the corresponding unmount lifecycle, and `useOnceEffect` if you need React 18 Strict Mode double-invoke protection.

## Usage

```tsx live
function Demo() {
  const [value, setValue] = useState("UnMounted");
  useMount(() => {
    setValue("Mounted");
  });
  return <div>{value}</div>;
};

```

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