I am fairly new to the NHGIS, so forgive me if this question has an obvious answer. I am trying to find any information I can on a site where an archeology dig is being performed in Northampton County, Pennsylvania. The earliest data I found with applicable data is the 1960 census block groups data, however, I see there are no block group shape files for before 1990. How can I go about mapping this data? I tried joining the 1990 block groups and the 1960 census data and it did not work, so I assume this is not the right way to do it. Any help is appreciated
This Census Bureau chapter helps explain the history and construction of Census blocks and block groups. It’s important to be aware that in the 1960 census, the Census Bureau reported block statistics for only 295 cities with a population of 50,000 or more. The only city in Northampton County that passed this threshold was Bethlehem; you can find block statistics for the city in this census publication. In 1970, block group statistics are available for urban areas, including the Allentown-Bethlehem-Easton Standard Metropolitan Statistical Area (SMSA). For 1980, the census block program expanded to include, in addition to urbanized areas, all incorporated places of 10,000 or greater population. You should be aware that since blocks are routinely split and new blocks are created, a block in one year does not necessarily refer to the same area as a block with the same code in a different year.
IPUMS NHGIS does not provide any shapefiles for 1960 block boundaries. Our 1970 block boundary shapefiles include all or part of 21 metropolitan areas and our 1980 block boundary shapefiles include all or part of 148 metropolitan areas; however, neither of these currently cover any areas within Northampton County. The challenge lies in the fact that while the U.S. Census Bureau’s 1992 TIGER/Line Files include both 1990 and 1980 census block boundaries, the 1980 blocks are badly incomplete and often inaccurate. We will keep working to extend the files to include more areas in future releases.
I just wanted to follow up with some more details for you, Blaise. I don’t believe census block groups became an official geographic level in the Census until 1990. As Ivan mentioned, there were block statistics in 1960, but we don’t have GIS data to support their mapping.
I looked at this map for the 1970 census tract boundaries, and we do have them for Northampton County, PA. So, you could get 1970 demographic/housing data and tract boundaries for the county.
Sincerely,
Dave Van Riper
IPUMS