It has several twin towns: Port Lincoln, South Australia; Radomsko, Poland; Tangshan, China; and Neustadt an der Weinstraße, Germany.
The city of Lincoln is built at the point where there is a gap in the Lincoln Cliff (a limestone escarpment running north-south and rising to 200 ft/60 m in height, also sometimes called the 'Lincoln(shire) Edge' or 'Lincoln Heath'). The River Witham flows through this gap. Lincoln is thus divided informally into two zones, known locally as uphill and downhill.

The uphill area comprises the northern part of the city, on top of the Lincoln Cliff (to the north of the gap). This area includes the historical quarter, including the Cathedral, Lincoln castle and the Medieval Bishop's Palace, known locally as The Bail (although described in tourist promotional literature as 'The Cathedral Quarter'). It also includes residential suburbs to the north and north-east. The downhill area comprises the city centre (located in the gap) and the suburbs to the south and south-west. The aptly named street Steep Hill connects the two (although it is too steep for vehicular traffic, which must take a more circuitous route).

This divide marks out Lincoln from other historic cities in England and elsewhere in Europe. Whereas in most such cities, the chief historical buildings (cathedrals and castles) tend to be centrally located and intermingled with the present-day city centre, in Lincoln they are separate.

The divide was also once an important class distinction, with 'uphill' more affluent and 'downhill' less so. This distinction dates from the time of the Norman Conquest, when the religious and military elite occupied the hilltop. The construction and expansion of suburbs in both parts of the city since the mid-nineteenth century has diluted this distinction, nevertheless 'uphill' residential property continues to fetch a premium, and is almost invariably referred to as such in literature emanating from local estate agents. Membership of noted uphill organisations such as the Lincoln Astronomical Society, the Lincoln Backgammon Club, the Lincoln Uphill Gardeners' Club and the Lincoln Waits is seen as a mark of local success, and much prized.

In the UK government scale of economic deprivation for district councils which varies 1 to 5, Lincoln and Boston have been graded as 4. However, this is an average figure, with 'uphill' Lincoln being more likely to be around 2.