How to link to an HISTORICAL County Lines map for any Year and Geographic Area of Interest -- overlaid on Google Maps

NOTE:  This article relates to HISTORICAL County Lines.  Here are the instructions for linking to PRESENT-day County Lines.

If you have a website or blog and want to create a link to an HISTORICAL county lines map for ANY YEAR and ANY US STATE,  this article is for you!

Using the instructions below, you can create a link to Historical U.S. Counties on Google Maps for any historical year already zoomed into a particular State, and optionally display the labels showing the county names as of that historical year.

Here's how it works:   

To create a map zoomed into a state for a given year, create a link such as this:
https://www.randymajors.com/p/maps.html?state=CT&year=1788

To create a map zoomed into a state for a given year, and show county name labels, create a link such as this:
https://www.randymajors.com/p/maps.html?state=OR&year=1865&labels=show
    TIP: copy/paste the above links and customize to suit your needs

    To explain the above example links, there are three words (called "query parameters") you can use to create a link.  Note, they must be specified in the order shown. 
    • state - expects a 2-character state code as used by the USPS, for example, ?state=CT
    • year - expects a 4-digit historical year, from 1629 through 2000, for example, ?year=1788
    • labels - optionally shows county labels by using the word show, for example, &labels=show

    Here are the maps produced by the two examples above

    The first example links you to an Historical U.S. County Lines map centered on Connecticut, showing you the county boundaries as of 1788:
    Historical U.S. Counties on Google Maps example from 1788 Connecticut

    The second example links you to an Historical U.S. County Lines map centered on Oregon, showing you the county lines as of 1865 and labeling the names of the counties on the map:
    Historical U.S. Counties on Google Maps example from 1865 Oregon with county name labels

    A few important things to make this work:

    1.  You must use the question mark ( ? ) right after .html, as shown above and below
    2.  You must separate query parameters using the ampersand ( & ), as shown above and below
    3.  You must specify the query parameters in order: state, year and optionally labels

    TIP:  For simplicity, you can drop the https://www from the front and just create the link as:


    With this functionality, you can feel free to create links on your own website that open a window to the Historical U.S. Counties on Google Maps tool, already zoomed into your area of interest and showing county boundaries as of the year you're interest in!

    Share this with others who may find this functionality useful!


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