While part of the Kingdom of Hungary, the city was the economic and administrative center of the Hungarian county of Háromszék, which spanned the present-day Covasna County and parts of Brașov County. In the second half of the 19th century, Sepsiszentgyörgy witnessed the development of light industry, namely a textile and a cigarette factory was built. It became part of the Kingdom of Romania following the Treaty of Trianon in 1920, after the end of World War I. After the Second Vienna Award in 1940 the city came under Hungarian control for four years. Near the end of that period, the Sfântu Gheorghe ghetto briefly existed in the city. At the end of the Second World War the Paris Peace Treaties reaffirmed the city and the entirety of Transylvania as a Romanian territory. Between 1952 and 1960 it was the southernmost town of the Magyar Autonomous Region, and between 1960 and 1968 was part of the Brașov Region, abolished in 1968 when Romania was reorganised based on counties rather than regions.