The Republican Journal was established in Belfast, Maine, the seat of Waldo County, following the demise of the Waldo Democrat (1828-29). The Democrat had backed John Quincy Adams over Andrew Jackson in the 1828 presidential election, and when Adams failed to win, the paper went out of business. Robert White, Jr. and Cyrus Rowe purchased the Democrat's printing press. They began circulating the Republican Journal to 333 subscribers on February 6, 1829. White and Rowe staunchly supported President Andrew Jackson and the Democrats. The following year, Maine Working Men's Advocate (1830-34) was formed to bolster the cause of Belfast's Whigs.The Republican Journal was a weekly four-page, five-column sheet. The following prospectus appeared on the front page of its first issue:

We propose to publish in Belfast a new paper of this name to be devoted to Political, Local, Moral, Religious, Literary and Agricultural Information... The political character of this paper shall be decidedly democratic, and we shall never hesitate to avail ourselves of every suitable opportunity to propagate republican sentiments...

Rowe and White worked diligently on the Republican Journal, which flourished with 1150 subscribers by 1837. White retired the following year. Benjamin Griffin of Boston partnered with Rowe, with Griffin serving as editor. Rowe sold his interest in the Journal in 1843 to Benjamin Griffin, who owned the Journal with his brother George. Two years later, the Griffins enlarged the paper and began using engravings to illustrate articles. In 1846, Rowe bought out the interest of George Griffin, and Benjamin Griffin and Rowe operated the newspaper together. In January 1849, Rowe and Griffin sold the Journal to George Moore and Levi Wing, former apprentices. Moore became known across Maine for his fresh writing style.

The Republican Journal printed foreign, national, and local news. For a time, its front page carried a column "Farm, Garden and Household," which featured advice about feeding chickens, increasing egg production, and how to shoe a horse. Editorials, works of serialized fiction, and advertisements from local businesses could be found inside as well. The paper had a wide reach, employing correspondents from approximately 20 area towns.

In 1858, the Republican Journal changed hands yet again when William H. Simpson assumed ownership. George Moore remained editor until 1861 when Simpson took over. The latter had begun his newspaper career as a 15-year-old apprentice at the Journal in 1840. After learning the trade, Simpson worked for other local newspapers, was a reporter for the Boston Post (1842-1956), and then purchased the triweekly Kennebec Journal (1841-64). Simpson sold the latter to James Blaine in 1854 and four years later purchased the Republican Journal. The Journal published news of the Maine regiments in the Civil War, sometimes taking as many as three of its four pages to share news with the families. Simpson had opposed slavery and objected to the South's wish to secede from the Union. Although Simpson supported the troops, he disagreed with the war. On July 22, 1864, when Lincoln called for another 500,000 soldiers, Simpson published an editorial in the Republican Journal entitled: "More Victims for the Slaughter Called for, A Draft of 500,000 Men Ordered." In it he questioned the need for more bloodshed:

This will make with previous calls, two million five hundred thousand men, that have been called for and furnished to this administration to be sacrificed in this shocking warfare...It really seems as though Lincoln, envying the fame of Gengis Khan, is going to build a tower of skulls that would overtop that of the sanguinary Tartar...Is the bloody catalogue to stretch to the crack of doom? Will the people vote for another four years of this?

In August, Simpson was charged with treason and inciting resistance to war. He pled not guilty, and eventually the charges were dropped. Despite his acquittal, he voluntarily stopped the presses at The Republican Journal on December 2, 1864. However, Simpson assured his readers that "as soon as a changed condition of the country and more encouraging business prospects should permit" he would relaunch the newspaper. Publication resumed on July 20, 1866. During the suspension, locals in Belfast found war news in the Republican newspaper, the Progressive Age (1854-89). Simpson who had fiercely advocated Democratic principles, shifted his allegiance to the Republicans on July 3, 1879 due to the financial tendencies of the Democratic Party. He retired after 22 years on September 30, 1880.

The Republican Journal was taken over by The Republican Journal Publishing Co. in October of 1880, which for 44 years was headed by Charles Pilsbury. During this period, the Journal continued to expand, and in 1892 it doubled in size from four to eight pages. In 1924, Pilsbury was succeeded by local merchant and president of the Belfast and Moosehead Railroad, Nathan Small. Another businessman, Roger Brace, took over direction of the paper, and by 1949 the Journal had expanded to 10 pages and 3,000 subscribers. By 1965, the Journal had two sections totaling 18 pages.

After Roger Brace's death in 1966, his son Russell Brace took over as publisher. Allen Brown was named editor the next year. Brown had strong opinions and was not afraid to take on local businesses and politicians when he disagreed with their policies; thus the editorial page of the Journal was often filled with local skirmishes. In the 1970s, Journal Publications became a subsidiary of Diversified Communications. The Republican Journal is still in publication today.