The county has twelve townships covering a total area of 375 square miles. The incorporated cities are Portland, 5,276, and Dunkirk, 3,588; towns: Redkey, 1,370; Pennville, 578; Bryant, 319, and Salamonia, 180. Jay County population in 1890 was 23,478; 1900, 26,618; 1910, 24,961; 1920, 23,318; 1930, 20,848.

Portland is located forty-two miles north of Richmond and is served by three railroads. The city has a number of manufacturing establishments. Chiefs among the products are lumber, flour, automobile parts, shirts, and overalls.

The city has one of the finest courthouses in the state. On the grounds there is a monument to John P. C. Shanks, erected in 1924 by the Mississinewa Chapter of the Daughters of the American Revolution In the corridor of the building is a bronze tablet dedicated in 1926 to the soldiers of the Revolutionary War. One-mile southeast of Portland is another marker placed by the Daughters of the American Revolution and located on the site of the Old Liber College, now out of existence. The other outstanding and historically significant marker placed by the Mississinewa Chapter of the Daughters of the American Revolution may be found one half mile north of the Jay-Randolph County Line, on Road 27. At this point the road crosses the old boundary of the territory ceded by Miami Indians to the United States in the Treaty of St. Mary's, Ohio, 1818.

The Pennville Historical Society has erected a marker two and half miles north of Pennville. It is a marble tablet which stands near an ancient house in the Quaker Trace, in memory of Eliza Harris of "Uncle Tom's Cabin" fame. Eliza is said to have stopped here in her flight to Canada.

The second city of the county, Dunkirk, is located eighteen miles northeast of Muncie and is served by one railroad. Chief among its industries are glass factories. It is a center of dairying, agriculture, and livestock raising.

Redkey is located eighteen miles northeast of Muncie and is served by one main railroad. Its products include tile, cement blocks, tools, and canned goods. The natural gas and oil fields are important.

This county has twenty-one manufacturing establishments, according to the federal census of 1935. These employed 2,148 wage earners on total payrolls of $1,941,178. The value of manufactured products was $8,013,572.

Jay County had 2,463 farms averaging 95.1 acres each. Their total value was $10,358,757. A total of 70,912 head of livestock was reported.

Total county tax valuation for the year of 1936 was $22,648,235.