Mengjin County , located in the hilly and mountainous areas in the central and western regions of Henan Province, is one of the counties under the jurisdiction of Luoyang City. It is 110 kilometers away from Zhengzhou in the east, 90 kilometers away from Sanmenxia in the west, adjacent to Luoyang City in the south, and adjacent to the Yellow River in the north. The county has jurisdiction over ten towns and two industrial clusters, 219 village committees and 9 neighborhood committees, with a total area of 758.7 square kilometers. The county government is located in Chengguan Town. According to the data of the seventh census, as of 0:00 on November 1, 2020, the permanent population of Mengjin County is 416845.

In 2019, the county's GDP will exceed 35 billion yuan, and the general public budget revenue will exceed 1.8 billion yuan, ranking 80 among the top 100 counties in six provinces in central China.

In March 2020, it won the title of National Advanced County for Village Clean Action, and was praised by the Central Agriculture Office and the Ministry of Agriculture and Rural Affairs. On July 29, 2020, it was selected into the list of reconfirmed national health towns (counties) in 2019.

In March 2021, the State Council approved the cancellation of Mengjin County and Geely District of Luoyang City and the establishment of Mengjin District of Luoyang City. The administrative regions of the former Mengjin County and Geely District are the administrative regions of Mengjin District.