Frequently Asked Questions

Who writes the stories/sign text?

The staff members of the National Register Sign Program write the historical marker sign text which appear on this website and app as "stories." Each National Register form includes a period of historical significance as well as architectural significance. These significant features of a site are taken into consideration alongside state education objectives such as Indian Education For All and the general promotion of Montana culture and heritage. Sign text information is reviewed by a Review Board.

What research methods are used?

The sign texts are interpreted information based on research culled from primary and secondary source materials. Sources may include newspapers, city directories, books, diaries, manuscripts, etc. Staff members of the Outreach and Interpretation (O&I) program retain copies of this information for their records. Additional property information, communication, maps, and photographs are retained with original copies of National Register forms at the State Historic Preservation Office (SHPO). 

Why aren't all sites available online?

Sites with historical markers are included on this platform once information has been reviewed, photographs identified and digitized, and latitude and longitude have been verified against the original National Register forms. This is an exhaustive process, which is why the MHS is focusing on broad themes and historic districts in separate regions of the state. 

Why do some sites direct to the local town?

Some National Register nominations requested restrictions on access and publication. We chose to indicate the closest town in order to share regional information, but limit access to these sites.

What do the colors and symbols on the online map mean, where is the key?

The ExploreBig map uses density-based clustering to visualize marker density at various zoom levels. This keeps viewers from being overwhelmed by dozens of stacked pins. As you zoom in, the clusters disperse and you see only the pins, as you zoom out, the markers continue to cluster until you eventually see a single cluster with the total number of stories on ExploreBig.

At less than 100 pins the cluster is yellow, under 10 pins the cluster is green. Pins with stars indicate featured stories.

This feature is only available on, it is not available on the ExploreBig app.

Where should I report misinformation?

Misinformation abounds. We are well aware of this and we do not want to contribute to it. Please secure documentation which shows the correct information and share this with the ExploreBig team at 

Can I share my photos?

Thank you for your offer. We prefer to include historical or documentary photographs at this point and we are able to work with local libraries, museums, historical societies, or non-profits who are interested in sharing their digitized photographs and granting us a single-use license to display their images.

Please contact us at for more information about contributing to this project.