The first man to make permanent settlement in the Plum Grove community was Joseph H. Adams. It is thought that he was the first white man to make the trip from Emporia to the Whitewater River. The story has it that the Whitewater River was originally called the White Woman River by the Indians, because of a white woman they had killed. Her body was thrown into the stream. Charles Lyon was another early homesteader. He married Harriet Adams, daughter of Joseph H. Adams. Mr. Lyon died of exposure while on a buffalo hunt with James R. Mead west of Wichita. Later Mrs. Lyon married John R. Wentworth who made final proof on the Lyon homestead [east of the Whitewater River]. (0. Claassen, Whitewater Centennial 94)

The first post office in the township was Plum Grove, located at John R. Wentworth's, and he was the first postmaster and the office was named for a thicket of plum bushes near the Wentworth house on the east side of the Whitewater. The office was established in the fall of 1871 and was supplied with mail from Towanda, at first once a week, and afterwards two mails a week. In 1872 Drake & Lobdell erected a building and put in a stock of general merchandise, which was the first store in the township. Later a Mr. Stewart opened another store.

After the railroad bonds were voted and a prospect for a road seemed quite certain, the stores and post office were moved over on the proposed line of the road a mile and a half west of the Wentworth Plum Grove location. This placed the new Plum Grove on the west side of the Whitewater River in the southeast corner of section one in Milton Township and the southwest corner of section six in Plum Grove Township. The Panic of 1873 caused the Chicago, Kansas, and Nebraska Railroad to postpone and later abandon its plan to build a railroad through Plum Grove. This severely restricted the town's early development. It was not until the late seventies that the town enjoyed its most active growth. Stark Spencer operated a general merchandise store, a saloon in the basement of the store, and a jail at the back of the saloon. He was also justice of the peace and postmaster. (0 Claassen 94)

A mail route was established from Peabody to Holden, in Milton Township, and to Plum Grove, and Oliver P. Bruinback carried the mail twice a week, walking and carrying it on his back. Some-time later the route was changed to run from Newton to EI Dorado, and another post office was established in the Plum Grove Township at the house of W. H. Randall.

This post office was named Ayr and Mrs. Randall was appointed postmaster. When the town of Potwin was started, the office was moved there and the name changed to Potwin.

The new town of Plum Grove on the west side of the Whitewater had two general stores, a drug store and a blacksmith shop. Stark M. Spencer was one of the merchants, M. C. Snorf the other. Dr. I. V. Davis had the drug store and practiced medicine, and W. W. Kemper had a blacksmith shop. A school house was built and the prospect was good for a nice little country town. In 1885, when the MissouriPacific railroad was finished, Plum Grove, being bypassed by the line, was divided, part going to the town of Brainerd and part to Potwin. (Mooney)