Warnham LNR is a 38.4-hectare (95-acre) Local Nature Reserve in Horsham in West Sussex.

It is owned and managed by Horsham District Council.

[1][2] The principal feature of the site is the 7-hectare (17-acre) Warnham Millpond, together with its islands and marginal vegetation.

Boldings Brook runs through the site and in the winter it floods areas of wet grassland and willow carr.

[1] There is access from Warnham Road.