Sinsheim is a town located in southwestern Germany within the state of Baden-Württemberg. It sits in the Rhine Neckar Area, positioned approximately 22 kilometres southeast of Heidelberg and 28 kilometres northwest of Heilbronn. The municipality lies in the Rhein-Neckar district and encompasses an area of 127 square kilometers. The Elsenz, an unnavigable left-bank tributary of the Neckar River, flows through the town before reaching the Neckar at Neckargemünd.

The region has been settled since 700,000 BC, evidenced by the discovery of Homo heidelbergensis fossils in nearby Mauer. The Romans ruled the area from 90 AD to 260 AD, and the city was possibly founded around 550 AD by the Frankish nobleman Sunno. It was first historically mentioned in 770 AD in the Codex of the cloister Lorsch. Sinsheim received city rights in 1192, a privilege granted by Henry IV, Holy Roman Emperor.

The town consists of a centre and twelve suburban villages, including Steinsfurt and Weiler. Notable landmarks include the medieval city core and Burg Steinsberg, an octagonal fortress from the 13th century that overlooks the area. The Auto & Technik Museum in Steinsfurt is a major attraction, housing historic vehicles and supersonic aircraft like the Concorde. The Rhein Neckar-Arena, home to TSG Hoffenheim, is also a significant local feature.

Sinsheim attracts over one million visitors annually to its technology museum and hosts various industrial events at its trade fair area established in 1989. The Altes Rathaus serves as a museum for the town and its role in the 1848 revolution. The town is also known for its connection to Franz Sigel, a Union general in the American Civil War, and features cultural sites like the Museumshof Lerchennest dedicated to Frederick II of Prussia.

The population was 37,036 as of 2024. Traditionally agricultural, Sinsheim became an industrial centre after the A6 Autobahn opened in 1968, connecting it to major cities like Mannheim and Stuttgart within an hour by car. The town is served by Sinsheim station on the Elsenz Valley Railway, which opened in 1868, facilitating regional travel and access to the broader Rhine Neckar transport network.