Newnham is a small village and civil parish in the North Hertfordshire district of Hertfordshire, England. It lies north of the town of Baldock. It shares a grouped parish council with the neighbouring parish of Caldecote. At the 2021 census the parish had a population of 88.
St Vincent's Church dates back to the 12th century, and features several medieval wall murals.
The solicitor and historian Reginald Hine (1883-1949) was born in Newnham Hall.
There are three tiers of local government covering Newnham, at parish, district, and county level: Caldecote and Newnham Parish Council, North Hertfordshire District Council, and Hertfordshire County Council. The parish council is a grouped parish council, also covering the neighbouring parish of Caldecote.