Amsterdam 

Amsterdam, the other hamlet of Liberty Township, is situated in the western part. A blacksmith shop was opened by Charles Wingard in 1874, and several houses cluster about it. The population has never, owing to the difficulty attending the taking of a correct and accurate census, been computed, but it is variously estimated at from ten to twenty-five.

History of Mercer County, 1888, page 558

At Amsterdam or "Yellow Horse," in the west part of [Liberty] township, a blacksmith and wagon-shop was opened by Charles Wingard, about 1874, and is still [1877] owned by him.

History of Mercer County, 1877, page 56

Landowners and Businesses in and near Amsterdam, according to the 1873 Combined Atlas for Mercer County: J. Uber, M. R. Uber, G. Uber, D. Uber, J. Sweitzer, Mrs. Scot, F. Chopin, Mrs. Dr. A. Apley, J. Nelson, C. Pearson, A. Uber, German Reformed Church, School House No. 3, old store, saw mill and blacksmith.

The pioneer sawmill of the Uber family [was] in the western part of the [Liberty] township. The Uber mills along the Butler turnpike were the foundation of a small hamlet, and the presence of a German Lutheran church, dating from about 1816, and the nationality of many of the residents caused the name Amsterdam to be applied to this locality. 

Twentieth Century History of Mercer County, 1909, page 161