Mill Creek was made a separate township in November, 1849. Jacob Reed is thought to have been the pioneer of this vicinity, having come in 1796, and being the only settler of whom record is preserved during the closing years of the century. Adam Carnahan was a settler about 1800, having been an unsuccessful claimant in two other townships. The settlement of the township did not progress very far until the second decade of the century. Patrick Kilgore, Francis Dunn, John Montgomery were founders of families here in the  early part of the century.

Some of the early institutions of the township were a school taught near the locality later known as Kerrtown about 1808, Allen Dunn teacher; Rocky Spring church (Associate Reformed), organized about 1810, which with its cemetery stood near the Sandy Lake township line; a grist mill erected about 1815, by Samuel Glenn.

In the northeast corner of the township French Creek postoffice was established in March, 1837, John McCracken and Francis Dunn being the only two postmasters. The office was abolished in 1876. North Sandy postoffice in the eastern part of the township was established in December, 1868, John A. Glenn postmaster, and was discontinued a number of years ago.  

The borough of New Lebanon has long been the principal commercial center of the township.

Twentieth Century History of Mercer County, 1909, pages 165-166