Kasimovsky District () is an administrative and municipal district (raion), one of the twenty-five in Ryazan Oblast, Russia. It is located in the north of the oblast. The area of the district is . Its administrative center is the town of Kasimov (which is not administratively a part of the district). Population: 29,602 (2010 Census);
Within the framework of administrative divisions, Kasimovsky District is one of the twenty-five in the oblast. The town of Kasimov serves as its administrative center, despite being incorporated separately as a town of oblast significanceâÂÂan administrative unit with the status equal to that of the districts.
As a municipal division, the district is incorporated as Kasimovsky Municipal District. The town of oblast significance of Kasimov is incorporated separately from the district as Kasimov Urban Okrug.