Jacksonville, the name of several towns in the United States, of which the chief are: - (1) A town in the N.E. of Florida, situated at the mouth of St. John's River. It has a large export and coasting trade. It is also a great health-resort. (2) A town in Illinois, 30 miles W.S.W. of Springfield. Here are several State institutions (for the blind, the insane, etc.), a free library, and twenty-two churches; also Illinois College and a Conservatory of Music. It stands in the midst of an undulating prairie.