Holy Cross is a city in Dubuque County, Iowa, United States. It is part of the 'Dubuque, Iowa Metropolitan Statistical Area'. The population was 339 at the 2000 census. Holy Cross is located at 42°36′1″N 90°59′40″W / 42.60028°N 90.99444°W / 42.60028; -90.99444 (42.600334, -90.994557). According to the United States Census Bureau, the city has a total area of 0.3 square miles (0.7 km²), all of it land.