Including Arnö, the locality on the southern shore of the bay just a couple of kilometres from the city centre, Nyköping would have above 36,000 inhabitants.

It forms a wider conurbation with the neighbouring minor municipality and town of Oxelösund 10 kilometres (6.2 mi) south of its outskirts.

The municipal border between Nyköping and Norrköping marks the point where the historical lands Götaland and Svealand converge on the east coast.

It retains an oceanic/continental climate hybrid, causing warm summers and winters around the freezing point with variable snow cover.

The business created a spin-off named ANA, which licence-built American and English cars, as Plymouth, De Soto, Hillman and Sunbeam.

But when GM bought SAAB from Investor AB, the headquarters was moved back to Trollhättan and about two thousand lost their jobs.

Between 1941 and 1980, the nearby Stockholm Skavsta Airport hosted the Södermanland Wing (F 11), which had three squadrons with reconnaissance aircraft.

The northern areas of the city is on exactly the same parallel of 58° 46' N as Canadian "polar bear capital of the world" Churchill, demonstrating how warm the climate is in comparison in spite of its northerly latitude.

The southern edge of the municipality also straddles the same parallel as the northernmost point of mainland Scotland at Thurso – that has a much more narrower range of temperature.

The southern edge of the municipality is the southernmost point of Svealand, the middle of Sweden's traditional three crown lands that once formed the country.

The city is located at a few miles more southerly latitude than the country's northernmost west coast town of Strömstad.

All automobile bridges except E4 also carry pedestrian sidewalks, which means transport is seldom made longer than the actual distance.

There is also a small pedestrian bridge in an unpopulated nature reserve called Hållet that is very close to the E4 route.

This is due to the port being some 15 kilometres from open sea as opposed to Oxelösund's position on the edge of the peninsula.

Even though Nyköping is a relatively flat city there are some hills in the northern parts of the town, barely reaching 50 metres altitude.

The rural localities of Sjösa, Bergshammar, Svalsta and Enstaberga located within 10 kilometres (6.2 mi) are connected to the city centre by cycle tracks with permanent lighting.

In addition there is a nature and coastal area called Tjuvholmen east of the city centre that is part of the locality with many holiday homes.

Tjuvholmen lacks an asphalted access road and is in general seen as a rural area in spite of its proximity to the city centre.

There is also lighted cycling tracks all the way south roughly 15 kilometres (9.3 mi) to the neighbouring city Oxelösund, making pedestrian and biking transport to nearby areas effective and avoids potentially dangerous contacts with motor vehicles.

As typical of southern Sweden there is a slight seasonal lag, meaning that the warmest period is often occurring during the second half of summer.

The city is yet to have a team in the major football or hockey leagues of Sweden, with stints in the second tiers being the greatest achievements for both main sides.