CASPER, the second city of Wyoming, U.S.A., on the North Platte river, in the central part of the State ; the county seat of Natrona county. It is on Federal highways 20 and 87E, and is served by the Burlington and the Chicago and North Western rail ways. In 1900 the population was 883 ; in 1920, and in 1930 Federal census 16,619. It is the industrial, financial and trading centre for a large part of the State, and one of the largest oil-refining centres in the country. Great quantities of petroleum products, wool, sheep and cattle are shipped. Teapot Dome and Salt Creek (20,000ac.) oil-fields lie about 40m. N. ; Big Muddy field, tom. east. The city has four refineries, which use an average of over 50,000 bbl. of crude petroleum daily. The assessed valua tion of property (exclusive of the refineries) was $22,394,240 in 1927; bank debits in 1926 amounted to The city owns a park of 40oac. on top of Casper Mountain, 8m. to the south, and Old Fort Caspar, which guarded the principal crossing of the river in the days of the covered wagon, now belongs to the city. Goose Egg Ranch, a social centre in the early days of the cattle kings, is 14m. S.W. ; Hell's Half Acre, a county park of scenic marvels, 45m. W.; and 51m. S.W. is Independence Rock, a great mass of black granite, a landmark on the old Oregon Trail, on which many of the pioneers cut their names, with dates as far back as 1832. Until 1847 the site of Casper was known as The Upper Crossing of the Platte; from 1847 to 1858 as The Mormon Crossing and Ferry; from 1858, when a bridge was built, to 1865, as Platte Bridge Crossing. In 1865 the fort was renamed in honour of Lieut. Caspar Collins, who was killed in an attack on the Indians on July 26, 1865. The town was founded on June 16, 1888, when the first railway train arrived, and was incorporated in 1889. The spelling of the city's name is due to a mistake on the part of a railway clerk.