Dacheng County is located in Langfang prefecture-level city (renamed Langfang Prefecture after Tianjin became a municipality), Hebei province, China.
It is the southernmost county-level division of the prefecture-level city of Langfang. 'Great City') is a county in the central part of Hebei province, China, bordering Tianjin to the northeast. It was renamed Langfang Prefecture after Tianjin became a municipality and finally upgraded into a prefecture-level city in 1988. 
