HATFIELD — A century ago, and many years before Interstate 91 was constructed, Hatfield was connected to neighboring and nearby Franklin County communities Whately, Deerfield and Greenfield via a trolley route.

On Saturday, the public is invited to retrace the way of the trolley, following River Road north from Hatfield center, through Whately to South Deerfield — where there once was a popular dance pavilion at the base of Mount Sugarloaf — and moving past the Bloody Brook monument, before continuing on Route 5 and 10 to Deerfield and Greenfield.

The event, supported by the Massachusetts Cultural Council and the Pioneer Valley History Network, is being put on following a recent acquisition by Historic Deerfield of a set of 52 original surveyor’s maps of the trolley route as it existed in 1915.

From 9:30 a.m. to noon, the four museums in the communities will be open and various trolley-related items from their collections, such as pictures, postcards, tickets and tokens, will be exhibited to show how people used these street railroads to move around the Pioneer Valley.

Meg Baker, curator of the Hatfield Historical Museum and curator at the Historical Society of Greenfield, said that the first electric street railroads came in 1895 and during World War I there were more miles of street railroads in western Massachusetts than there were miles of railroads.

“Workers could use the trolley to get to the factory or mill, people working in one town could live in another, and weekend excursions to the country for picnics and swimming became widely accessible,” Baker said.

The original surveyor’s maps, bought from the online auction site eBay, show a trolley route from Hatfield to Whately and Deerfield, and over the Connecticut River into Greenfield.

Quick thinking and collaboration allowed the maps to become part of the collection of the Memorial Libraries in Historic Deerfield, said Librarian Jeanne Solensky.

“There’s a lot of information in these maps,” Solensky said. “They are printed on specially treated linen and some of them are quite interesting.”

Trolleys left each town center on a schedule, but in between, stops were largely “at will.” Based on original maps, and records held at the various museums, likely places that the trolley would have stopped have been identified and will be flagged with lawn signs on Saturday.

Trolley maps can be picked up at the participating museums, which include the Hatfield Historical Museum at 39 Main St., housed upstairs in the 1894 Memorial Hall, and which once had trolley tracks out front; the Visitor Center at Hall Tavern at Historic Deerfield, 80 Old Main St.; the Whately Historical Society Museum, in the Town Hall at 194 Chestnut Plain Road, just six minutes off the trolley line; and the Historical Society of Greenfield, 45 Church St., which just opened a new exhibit on transportation history.

For more information, email hatfieldhistoricalsociety@gmail.com.