The University of Delaware, Department of Mathematical Sciences has 1798 tax records in databases that are free and available for download. 1798 tax records are not complete for any area and areas include Philadelphia, Maryland, and New Jersey.
“The United States Congress, under the Act of 14 July 1798 (1 Stat. 597) created the first property tax of its citizens. The 1798 Federal Direct Tax Lists provides ownership, rental and descriptive information for every house then existing. In the majority of the States, these lists have not survived. Pennsylvania does have the most complete list and is available on microfilm. The datasets in this collection were compiled by University of Delaware faculty and staff from original 1798 Direct Tax Lists.”