What was the First American football offensive formation?

Answer 1

While it cannot be said with 100% certainty that this was the first offensive formation, but the single wing formation is one of the earliest known offensive formations in football.

It was originally developed by Glenn "Pop" Warner back in the early 1900's. It is the precursor of the modern day Spread Option offense. It was used as early as 1907, 13 years before the NFL was founded.

The formation featured an strong side offensive line with four backs in the backfield. In football the traditional offensive line has a Tackle/Guard/Center/Guard/Tackle formation. In the Single Wing the line has a different set up. The line formation typically goes End/Guard/Center/Guard/Tackle/Tackle/End.

In the backfield, you have 4 backs, the quarter back, who lines up behind the interior tackle on the strong side of the line, the full back, who lines up between the center/guard on the strong side one step behind the QB, the tailback, who lines up behind the center/guard on the weak side one step behind tailback, The split wing is positioned one step behind the line, just outside of the end on the strong side of the line.