Recap
The New York Pro Football League (NYPFL) was a professional American football league, active in the 1910s, and based in upstate New York, primarily Western New York. The league's formation was highly informal. The teams were largely clustered around the two cities of Rochester, New York and Buffalo, New York, with rural teams to fill the differences. Rochester had built its reputation around a strong "sandlot football" circuit, for instance, and was most popular when it consisted mostly of local teams.
Rochester's best team, the Jeffersons, was instrumental in bringing the NYPFL and the Ohio League together to form the NFL. Jeffersons owner Leo Lyons suggested to Bulldogs coach Jim Thorpe and owner Ralph Hay that a league format could eventually become as popular as Major League Baseball.
Between 1920 and 1921, the league's best teams were absorbed into the National Football League, though none survive in that league today. The circuit continued to exist even after the birth of the NFL (with the NYPFL teams continuing to play in both circuits), with the league finally dwindling away in the late 1920s and early 1930s
I sincerely appreciate the research work, and the information being shared. It is important and interesting history.