From the Wikipedia page 
The Ga West Municipal is one of the ten (10) districts in the Greater Accra Region of Ghana. Its capital is Amasaman. The district is among the new districts and municipalities created in 2008 by the then President, John Kufuor. It was inaugurated on 29 February 2008.
The Ga West Municipal Assembly was established by L.I 1858 on November 2007 and it is the gateway to Accra on the Kumasi Accra route. The Municipality lies within latitude 50°48’ North, 5°39 North and longitude 0°12 west and 0°22 West. It shares common boundaries with Ga East and Accra Metropolitan Assembly to the East, Akuapem South to the North and Ga South to the south and West. It occupies a land area of approximately 305.4sq km with about 193 communities. Both Ga East and Ga South were created out of the then Ga District now Ga West Municipal Assembly