The community was first known as Senachwine, which was the name of a Pottawatomi Indian chief who lived and hunted in that area, and was buried about a mile away from the present site in 1831. The community was first laid out in 1835 by B.M. Hayes, but nothing came of it and took a second effort by land owners Peter Barnhart and Cortland Condit to get the village going along the banks of the Illinois River, south of where the river bends near Hennepin.  

The name Putnam came from Israel Putnam [1718-1790], a career military man who served in the French & Indian War, Pontiac's War, and was a major general for the Continental Army during the Revolutionary War. The name of the railroad station that served the community for the Peoria and Bureau Valley RR was changed from Senachwine to Putnam in 1883. At that time, this was the only railroad stop in the county and the population was somewhere around 800 people. 

The history of education in Putnam is in need of research. It is believed that the people of Senachwine Township started schooling their children somewhere in the late 1800’s and continued doing so in grades 1-12 until after World War II when talks began with neighboring Henry Township in Marshall County in 1946 while 27 students were enrolled at Senachwine Township HS. The state of Illinois was encouraging consolidation of schools that were the size of Senachwine because they would not give them state funding unless they had at least 40 students enrolled or had so much in assessed farmland values. As a result, both school boards worked together and got voter approval to merge in March 1947, with all high school students going to the new Henry-Senachwine Consolidated High School beginning in the fall of 1947.

No. of districts consolidated:          4

Square miles:                               24

Assessed valuation:                      $438,398

Cost of house:                              $14,000

Annual tax levy:                            $6,320

Tax rate:                                      1.45

Annual tax levy before:                  $1,960

Teachers now:                              5

Teachers before:                           4

Enrollment now:                           92

Enrollment before:                        54

Enrollment in grade school:           60

Enrollment in high school:             26

No. studying agriculture:               4

No. studying manual training:        8

Aid from vocational fund:               No

Public conveyance:                      No

Years of high school course:         4

Months in year:                            9