Conrad Keefe Cyr was an American jurist who served as a United States circuit judge of the United States Court of Appeals for the First Circuit from 1989 until his death. He was previously a United States District Judge of the United States District Court for the District of Maine.

The U.S. District Court for the District of Maine is the U.S. district court for the state of Maine. The District of Maine was one of the original thirteen district courts established by the Judiciary Act of 1789, even though Maine was not a separate state from Massachusetts until 1820. The court is headquartered at the Edward T. Gignoux United States Courthouse in Portland, Maine, and has a second courthouse in Bangor, Maine.