This paper discusses how the original manuscript Census records can be used to derive information on employers and their workforce, self-employed sole proprietors, and the acreage of farms. It assesses how the content changes over time and has to be handled in database construction, focusing on issues of completeness; identification of employers, own account and workers; occupational coding; gender coverage; identification of portfolio businesses; partnerships; and location. This underpins database design for Entrepreneurs 1851-1911 to be deposited at UKDA.