The paper presents an initial analysis of the distribution of unemployment by region among skilled engineering workers in the period 1851–1914. Statistics are derived from the unemployment insurance system operated by the Amalgamated Society of Engineers (A.S.E.), the largest national union in Victorian Britain. The history of such union-run insurance schemes is briefly sketched, the focus on the A.S.E. being justified by its size, the length of its records, and the crucial economic position of its members. Methods of calculating an accurate unemployment rate from the available data are discussed and a crude monthly series for the entire period is presented. For each of the eight major economic depressions in the period, a sequence of maps depicts regionalunemployment. Various other primary and secondary materials have been drawn on to corroborate the union unemployment statistics, and these suggest that the A.S.E. membership was, to some extent, representative of the industrial sector generally. The experience of the union in the depression years of 1858, 1862 and 1868 reflected that of the textile industry, while in later recessions the highest unemployment occurred in heavy engineering and shipbuilding districts. Regional and urban unemployment rates for the eight depressions are tabulated.