A circular bearing date September 9th, 1853, stating that the inhabitants of Castle Cary have for some time past felt that the growing importance of their market called for an increase of accommodation for those who frequent it. To supply that deficiency it was proposed to build a Market House at Castle Cary under the provisions of the Joint Stock Companies' Act, for the sale of Corn, Cheese, Butter, Meat, Vegetables, and other produce. The proposition had already received the approbation of the principal inhabitants, owners, occupiers of Land, and Corn Dealers of Castle Cary and its vicinity. As a result of the above circular the present Market House was built in 1856, the architect being Mr. F. Penrose. The undertaking was not a great success, and the shareholders were not burdened with dividend, but the Hall has proved of great service to the town.
The Castle Cary Market House is a distinctive mid-Victorian building in the centre of town made of local Cary stone. The Castle Cary Museum is located on the first floor of the building.