Újbuda is the 11th district of Budapest, Hungary. It is the most populous district of Budapest with 137,426 inhabitants. Until the 1890s, Újbuda's present territory was a field south of the historical town of Buda. The construction of a new residential area started in the 1900s, the present district was formed in 1930. From 1880 to 1980, Újbuda's population increased from 1,180 to 178,960. There are boulevards, avenues with tram lines, and communist-era housing estates in the district. Line 4 of the Budapest metro passes through Újbuda.