Leineschloss, Parliament building in Mitte district, Hannover, Germany

Leineschloss is a four-wing neoclassical palace on the Leine in Hanover's Mitte district, now the seat of the Lower Saxony Landtag. Its Leine side has three storeys under a steep mansard roof with small dormers, above a heavy stone base with arched windows. The Leinstrasse front carries a portico of six Corinthian columns with a flat pediment bearing the royal Hanoverian coat of arms, and Laves's projecting Winter Garden breaks forward toward the river.

The site was a Franciscan friary founded around 1300 and dissolved in 1533; from 1636 Duke George of Brunswick-Lüneburg converted it into a modest palace, and George I was born here on 28 May 1660. Laves rebuilt it in neoclassical form between 1816 and 1844, adding the six-column Corinthian portico. After Allied air raids destroyed it in the Second World War, Dieter Oesterlen rebuilt it from 1957 to 1962 for the Lower Saxony Landtag.

The name Leineschloss comes from the river Leine, on whose bank it stands. The former palace church, consecrated in 1642, served as the royal burial place; George I of Great Britain was born here in 1660 and was first buried in the chapel before his remains were moved to Herrenhausen after World War II. Since 1962 the Landtag of Lower Saxony has met in the building, and the former Winter Garden, built by Laves in 1839 for Queen Friederike's plants, is now the office of the Landtag president.

The building sits centrally near Hannover's main train station and is easily visible from the surrounding streets. The best views of the facade are from adjacent roads like Karmarschstrasse or from the opposite bank of the river.

During renovation work in 2016, workers uncovered human remains in the building's foundations, which sparked investigation into their link to a royal scandal from 1694. This discovery reopened a chapter of local history that had been buried beneath the structure for centuries.