The seat was created in 1997 and has always been represented by Members of Parliament (MPs) from the Conservative Party; like all British constituencies, it elects one candidate by the first-past-the-post voting system.

The constituency covers the towns of Sleaford and North Hykeham and a large area of rural Lincolnshire south west of Lindsey.

[2] The inclusion of North Hykeham in the constituency title was criticised by the author and psephologist Robert Waller in 1995, on the grounds that North Hykeham was effectively an overspill area of the City of Lincoln; however, not on the grounds of its actual inclusion, as its local government authority has long been seen as linked with the villages to the south in this seat, and wholly separate from the city.

Following a local government boundary review which came into effect in May 2023,[5][6] the constituency now comprises the following wards of the District of North Kesteven from the 2024 general election: The areas within the constituency of Sleaford and North Hykeham are under the control and come under the responsibility of Lincolnshire County Council for the provision of certain public services, such as roads and local authority education.

[8] Douglas Hogg moved to represent Sleaford and North Hykeham from the previously existing Grantham constituency, a safe Conservative seat, which he had held since 1979.

[13] He stood down at the 2010 general election owing to controversy over his expenses claims, making him the first MP to resign because of the scandal.

[20][21] This triggered a by-election within the constituency, which was held on 8 December;[22] Caroline Johnson retained the seat for the Conservatives with a large majority.