Merrickville and District Historical Society is a volunteer-run organization based in the Village of Merrickville-Wolford, a beautiful historic village spanning the Rideau Canal, one hour south of the Nation's capital. MDHS encourages interest in the history and heritage of Merrickville-Wolford. MDHS also operates the seasonal museum at the Merrickville Blockhouse National Historic Site of Canada.

Tucked away on the Rideau Canal, a UNESCO World Heritage site, the Merrickville Blockhouse was built in 1832 as a defensive structure designed to protect British North America from American invasion. By the time of its completion the threat of invasion had passed and the Blockhouse was converted into a home for the lockmaster. In 1939 the Merrickville Blockhouse was recognized as a National Historic Site of Canada. MDHS was instrumental in preserving this building in the 1960's and has operated the Merrickville Blockhouse Museum since 1967.