Teesside is a built-up area around the River Tees in North East England, split between County Durham and North Yorkshire.

Created in 1968 by the merger of the county borough of Middlesbrough; the municipal boroughs of Stockton-on-Tees, Thornaby-on-Tees, and Redcar (except for a very small part); most of the urban districts of Billingham and Eston; smaller portions of the urban districts of Guisborough, Saltburn, and Marske-by-the-Sea; and parts of the rural districts of Stockton and Stokesley. Boulby Cliff, the highest cliff on the English coastline, was within its borders.

In 1974, however, Teesside split into the boroughs of Stockton-on-Tees, Middlesbrough and Langbaurgh (now Redcar and Cleveland).

The area covered by Hartlepool lies to the North of the Cleveland Fire Authority Area and consists ofeleven local wards and two fire stations (one wholetime, one on-call). These Wards range from areas of high social deprivation to areas of executive housing. The current population is over 93,000 living in over 42,500 homes. 

The area covered by Middlesbrough is in the centre of the Cleveland Fire Authority Area and consists of 23 local wards. It is the most densely populated and urbanised authority in Cleveland. Middlesbrough is bounded by the River Tees, North Yorkshire Moors National Park and two other local authorities. The current population is over 140,000 living in over 60,000 homes.

The area covered by Redcar & Cleveland lies to the east of the Cleveland Fire Authority Area and consists of 22 local wards. These wards range from large built up areas to small rural villages whichback onto heavy industry. The current population is over 136,000 living in over 62,000 homes.

The area covered by Stockton lies to the west of the Cleveland Fire Authority Area and consists of 26 local wards. These wards range from areas of high social deprivation to areas of executive housing. The current population is over 196,000 living in over 83,000 homes.