Calthorpe Broad is a 43.5-hectare (107-acre) biological Site of Special Scientific Interest east of Stalham in Norfolk, England.

[4] It is also part of the Broadland Ramsar site[5] and Special Protection Area,[6] and The Broads Special Area of Conservation.

[7] This broad has diverse fauna and flora.

Water plants include mare's-tail, water violet, blunt-leaved pondweed, spiked water-milfoil, floating scirpus, yellow water-lily and the nationally scarce water soldier.

[8] The site is private land with no public access.