The first known inhabitants of the area now known as Palmer Township were the Lenape Native Americans in the 17th century.

The main activity of Palmer Township during its earliest years was providing access roads from neighboring Easton to surrounding communities, including Bethlehem, Freemansburg, and Nazareth.

Among them were the Seipsville Hotel, which was built by the settler Peter Seip in 1760 at the crossroads of roads leading from Easton, Nazareth, and Hecktown.

The Seipsville Hotel was the first public house between Easton and Nazareth, and became a popular stagecoach stop for travelers passing through the Lehigh Valley.

[5] In 1977, the building, now known as the Seipsville Inn, was added to the National Register of Historic Places due to the significance of its architecture and engineering.

In the early 1920s, subdivision activity along inter-city trolley lines led to a building spurt in Palmer Township, which doubled the population within 10 years.

As a result, the township became seen as a desirable place to live for people who worked in other areas of the Lehigh Valley.

The population grew further in the late 1940s and early 1950s due to the expansion of water lines and the development of low-income housing.

Summers are typically warm and muggy, fall and spring are generally mild, and winter is cool to cold.

Rainfall is generally spread throughout the year with eight to 12 days of precipitation per month[10] at an average annual rate of 43.5 inches (110.5 cm).

The airport has direct flights to Atlanta, Charlotte, Chicago–O'Hare, Detroit, Philadelphia, and several cities in Florida.

North-to-south Pennsylvania Route 33 crosses the northwestern portion of Palmer, with an interchange at Tatamy Road within the township.

The Blue Line, LANta's Bus Rapid Transit service, serves Palmer Township at three stops: Stones Crossing, Greenwood, and 25th Street.

NJ Transit provides bus service from Center Square in Easton to Phillipsburg and Pohatcong in New Jersey along the 890 and 891 routes.

In September 2020, Amtrak, as part of its expansion plan, proposed restoring rail service between Allentown and New York City by 2035.

This largely single-track Amtrak route has been opposed by Norfolk Southern Railway, which acquired the Lehigh Line as part of its purchase of federally-founded Conrail in 1999.

In November 2008, the Lehigh Valley Economic Development Corporation (LVEDC) and both Lehigh and Northampton counties commissioned a study, exploring restoration of the Black Diamond service, which ran until 1961, which would likely entail extending New Jersey Transit's Raritan Valley Line to nearby Easton.

Other industries began to arise in the late 19th and early 20th centuries, including some iron ore excavation in the Fairview Knolls area and the cement industry near the Tatamy area; also at this time, the Taylor Wharton and Treadwell Engineering were established in Palmer Township to manufacture equipment mainly for railroad use.

Farming techniques gradually advanced in the area until by the late 1960s; almost 50 percent of the township was then farmland.

WDIY-FM, a National Public Radio affiliate located in Bethlehem, maintains a translator in Easton and broadcasts at 93.9 FM.

When Palmer's major roadway system first started to develop in the 18th century, dictated largely by the trails leading from Easton to outlying communities.

William Penn Highway, the first road built in Palmer in around 1755, led from Easton to Bethlehem.