Historical US Counties on Google Maps enhanced to match Census dates, adds townships

With Census season upon us, I’ve made a little update to the Historical U.S. Counties on Google Maps tool.

Now, when you search for a year that was also a U.S. Federal Census year (e.g. 1790-2020) , the date will automatically set to the day of the Census that year.

Per the Census Bureau, “From 1790 to 1820, the censuses were conducted as of the first Monday in August (August 2, 1790; August 4, 1800; August 6, 1810; August 7, 1820); the 1830-1880 and 1900 censuses were as of June 1; the 1890 census was as of June 2; April 15 was Census Day in 1910; and the 1920 census was as of January 1. Since 1930, Census Day has been April 1.”  Yes, since 1930, Census Day is April Fool’s Day…do with that what you will ;)

So, for example, if you’re using the Historical U.S. Counties Auto-Checker Chrome extension for Ancestry and FamilySearch, and happen to search a Census year, your map will open up linked to the correct census date, so you know you’re searching in the correct county for that ancestor in that year!

(See Historical U.S. Counties Auto-Checker overview and complete write-up, and join the nearly 1,000 people who have downloaded it for free here since its release a few weeks ago)

Here’s an example searching on Ancestry for a Robert Jones living in Springfield, Sangamon County, Illinois in 1820.

First, you’ll be surprised/indifferent/relieved to see that the Historical U.S. Counties Auto-Checker correctly tells you that Sangamon County did NOT exist in 1820, together with a handy link so you can see what DID exist! By the way, I didn’t type Sangamon County in the Search form, Ancestry’s auto-complete menu suggested it.  (see Auto-Checker screenshot below)

Click the “View MAP of 1820 Illinois counties” link in the Auto-Checker, and you’ll get a new tab showing you historical counties from that year, centered on Springfield!

First, you’ll notice that Springfield was in Madison County, Illinois that year!  (No, Springfield didn’t move…the county lines did.)

Next, you’ll notice that the date is set to 8/7/1820 since that’s when the Census was taken that year.  (see map screenshot below)

By the way, of course you can search on any exact date in the Historical U.S. Counties on Google Maps tool, but if you just type a four-digit year and it’s a federal census year, the date will default to the Census date that year!

And bonus for reading this far:  

In the lower left corner of the Historical U.S. Counties on Google Maps tool, you now have a checkbox to “Also show US townships“.   Those are present-day township lines, but they often will align with historical township names and provide additional local context.  Here’s what it shows if we click around Pleasant Plains just west of Springfield:

As shown above, Pleasant Plains is in Cartwright township.  Also, in the above example, I’ve checked “Also show present-day county lines“, so we can be relieved to see this really is where Sangamon County is today!

Happy searching and mapping!