This paper describes how individual entrepreneurs can be identified and extracted from the original Census Enumerators Books (CEBs) for 1851-81. It describes the early censuses and the method through which different groups of entrepreneurs can be identified, extracted and parsed, particularly focusing on identifying employee numbers of the businesses. It distinguishes between: employers with employees; own account proprietors; and people owning certain business assets. Constraints in the data are summarized and how information was infilled from other sources to correct for the substantial gaps and truncations in the I-CeM electronic records of the census, especially for 1851, 1861 and 1871.