Birkby is a hamlet in the Allerdale district of the English county of Cumbria, historically within Cumberland, near the Lake District National Park. It is located on the A596 road, 1.6 miles (2.6 km) north-east of Maryport + 26.2 miles (42.2 km) south-west of Carlisle. In 1870-72 it had a population of 157.

Birkby is in the parliamentary constituency of Workington. In the December 2019 general election, the Tory candidate for Workington, Mark Jenkinson, was elected the MP, overturning a 9.4 per cent Labour majority from the 2017 election to eject shadow environment secretary Sue Hayman by a margin of 4,136 votes. Until the December 2019 general election, the Labour Party had won the seat in every general election since 1979.The Conservative Party had only been elected once in Workington since World War II, at the 1976 by-election. Historically Birkby has been a Labour supporting area.

Before Brexit for the European Parliament its residents voted to elect MEP's for the North West England constituency.

For Local Government purposes it is in the Cumberland unitary authority area.

Birkby is in the parish of Crosscanonby which has its own Parish Council; Crosscanonby Parish Council.

• List of places in Cumbria