Places:

• Roscommon, town in Ireland
• County Roscommon, in Ireland
• Roscommon, Michigan, village in the United States
• Roscommon County, Michigan, county in the United States
• Roscommon Township, Michigan, township in the United States

Constituencies:

• Roscommon (Dáil Éireann constituency), Dáil constituency, 1923–69
• Roscommon (UK Parliament constituency), UK constituency in Ireland, 1800–85
• Roscommon Borough (Parliament of Ireland constituency), 1611–1800

Institutions:

• Roscommon railway station, Ireland
• Roscommon County - Blodgett Memorial Airport, Michigan, United States
• Roscommon High School, in Roscommon, Michigan
• Roscommon School, Primary School in Manurewa, a suburb of Manukau City, Auckland Region, New Zealand

Other:

• Roscommon GAA, the Gaelic Athletic Association board for County Roscommon, Ireland
• Earl of Roscommon, title in the Peerage of Ireland 1622–1850