Kings (Brooklyn) County, New York Genealogy
In 1898 the five boroughs consolidated into New York City. Each borough's border matches its county's border. This Wiki lists the most data about these at the county level except Brooklyn.
1664 Yorkshire became the first large government unit (not actually a county) organized by New York after the English took control from the Netherlands. It was divided into three ridings including West Riding (now Richmond, Kings, and most of Queens). 
1683 New York Province extinguished Yorkshire, creating Kings County from part of it. 
1898 The five boroughs were consolidated into New York City and her county governments were dissolved. The Borough of Brooklyn became a borough of Greater New York City, with the same borders as the former Kings County.
A wiki article describing an online collection is found at:
- Wikipedia contributors, "York Shire (Province of New York)" in Wikipedia: the Free Encyclopedia at http://en.wikipedia.org/wiki/York_Shire_(Province_of_New_York) (accessed 16 December 2011).
- Kathryn Ford Thorne, New York Atlas of Historical County Boundaries (New York: Simon and Schuster, 1993), 99. At various libraries (WorldCat); FHL Book 974.7 E7t.
- Wikipedia contributors, "Brooklyn" in Wikipedia: the Free Encyclopedia at http://en.wikipedia.org/wiki/Brooklyn (accessed 4 January 2012).