The International & Great Northern Railroad Company, a major component of the Missouri Pacific in Texas, was itself formed from the consolidation of two lines – the International Railroad Company and the Houston & Great Northern Railroad – on September 30, 1873.

The Houston and Great Northern was chartered on October 22, 1866, by the first legislature to meet after the Civil War. At the time of the merger, the Houston and Great Northern owned 252 miles of track between Houston and Palestine, between Houston and East Columbia with branches from Phelps to Huntsville, and between Troup and Mineola, Texas. The mileage of the Houston and Great Northern included the former Houston Tap and Brazoria Railroad and the Huntsville Branch Railway, which had been merged on May 8, 1873. The International was chartered on August 5, 1870, and at the time of the I-GN consolidation on September 30, 1873,  operated 177 miles from Hearne to Longview, Texas.

Despite the financial panic of 1873, the consolidated company continued to slowly expand, reaching Rockdale in 1874 and Austin on December 28, 1876. On December 1, 1881 the I-GN reached San Antonio and Laredo. The I-GN then acquired the Georgetown Railroad Company on June 2, 1882. The last major push of the century involved the aquisition of the Henderson and Overton Branch Railroad Company on September 27, 1880, but this line would notbe consolidated until August 31, 1911.

Jay Gould acquired control of the International and Great Northern in December 1880. The company was leased to the Missouri, Kansas and Texas Railway Company, another Gould company, for ninety-nine years on June 1, 1881, but the lease was canceled on March 2, 1888, and the railroad was again operated by its own organization.

During the 1890’s the International and Great Northern owned eighty-eight locomotives, sixty-one passenger cars, 1,919 freight cars, and eighty company service cars. Earnings that year included $1,076,695 in passenger revenue and $2,530,451 in freight revenue. The company owned 756 miles of track at the end of 1882 and would make no major expansions to this mileage until after the turn of the century.

On May 1, 1901, the I&GN merged the Calvert, Waco and Brazos Valley Railroad Company. In 1903 the railroad also acquired the Houston, Oaklawn and Magnolia Park Railway Company. Next would come the Henderson and Overton Branch, giving the International and Great Northern its peak of 1,106 miles. In addition, the I&GN owned the Austin Dam and Suburban Railway Company and a 50 percent interest in the Galveston, Houston and Henderson Railroad Company.

The Missouri Pacific Railroad Company, the Texas and Pacific Railway Company, and the I&GN had worked together as a system through the Gould holdings in each company rather than by any direct control by the MoPac. After the Gould family lost controlling interest in these railroads, the St. Louis-San Francisco Railway Company in 1922 attempted to acquire the I&GN. The International & Great Northern Railway had entered receivership and emerged in 1922 as the International – Great Northern Railroad.

Fortunately for Missouri Pacific, the Interstate Commerce Commission refused to authorize the Frisco’s purchase, but the threat of losing this major Texas connection prompted MoPac to begin acquisition of the I-GN. This was accomplished through the New Orleans, Texas and Mexico Railway Company (NOT&M), which bought the I-GN on June 20, 1924, on behalf of MoPac. When the NOT&M was itself acquired by the MoPac on January 1, 1925, the I-GN became part of the Missouri Pacific Lines, continuing to operate as a separate entity.  (source: George C. Werner – Handbook of Texas Online)