Al Majma'ah (Arabic: المجمعة) is a city and a governorate in Ar Riyad Province, Saudi Arabia. It is located at around 25°54′14″N 45°20′44″E / 25.90389°N 45.34556°E / 25.90389; 45.34556, and has an area of 30 000 square kilometers. The population of the town is around 45,000, while the population of the governorate as a whole is approximately 97,349. Al-Majma'ah Governorate borders the Eastern Province and Al-Qasim to the north, Thadig and Shaqra to the south, Rumah to the east, and Zulfi and al-Ghat on the west.
Founded in 1417 CE by an immigrant from the Shammar tribe, Al-Majma'ah was historically considered the capital of the region of Sudair. The city today contains a museum as well as an impressive mud-brick fort that dates to the 18th century.