1905, Treynor was Incorporated! The first mayor was Ferdinand Schoening. The businesses at this time were Treynor Savings Bank, two general stores, a furniture & implement house, a livery stable, two saloons, several blacksmith shops, and a number of small places of business. The independent school had an enrollment of 40 pupils.
Early in 1910-1920, a high voltage electrical system was installed for $6.000. Before that, many homes were lit by a home electric plant or carbide lights.
On June 29, 1911, the Treynor Shortline railroad was dedicated. The cost to build this railroad, which was shut down five years later, was $300,000.
Early in the winter of 1919-1920 a terrible coal shortage hit the nation, and Treynor, along with the rest of the states went under the Garfield orders whereby all businesses opened at 9:00 am and closed at 5:00 pm. Saturdays excepted. Churches were to remain closed except for a 3-hour service on Sundays. All social entertainments were called off, theaters, shows, dance halls, pool halls, bowling alleys, and other amusement places were ordered closed until further notice.
The new building for Treynor High School was dedicated in March of 1923. During this time, the price of a haircut was 50 cents.
In 1925, the population of Treynor was 223, compared to 204 in 1920. The current population is 919.