Who invented the odometer?

One of the earliest (chariot) odometers may have been designed by Archimedes

(287-212 BC) and was described around 27 BC. Some form likely existed before then as indicated by the recording of distances during the reign of Alexander the great (336-323 BC).

Chinese scientists independently created a form of odometer around the same time, notably the "drum carriage" later improved by Zhang Heng (87-136 AD)

Blaise Pascal designed a geared version for carriages in 1645, and a version was adapted to measure postal routes by Benjamin Franklin in 1775.

The modern automobile odometer was designed as a combination speedometer and odometer by brothers Arthur P. Warner and Charles H. Warner in 1903.