As Sibley pushed up the river, passing Fort Craig and brushing aside a small force at Valverde, the Colorado forces reached Fort Union. Between Fort Union and Albuquerque, which Sibley entered easily, was the turning-point in the campaign. On March 26, 1862, Major J. M. Chivington had a successful skirmish at Johnson's ranch in Apache Cañon, about twenty miles southeast of Santa Fé. Two days later, at Pigeon's ranch, a more decisive check was given to the confederates, but Colonel John P. Slough, senior volunteer in command, fell back upon Fort Union after the engagement, while the confederates were left free to occupy Santa Fé. A few days later Slough was deposed in the Colorado regiment, Chivington made colonel, and the advance on Santa Fé begun again. Sibley, now caught between Canby advancing from Fort Craig and Chivington coming through Apache Cañon from Fort Union, evacuated Santa Fé on April 7, falling back to Albuquerque. The union troops, taking Santa Fé on April 12, hurried down the Rio Grande after Sibley in his final retreat. New Mexico was saved, and its security brought tranquillity to Colorado. The Colorado volunteers were back in Denver for the winter of 1862-1863, but Gilpin, whose vigorous and independent support had made possible their campaign, had been dismissed from his post as governor. Along the frontier of struggle campaigns of this sort occurred from time to time, receiving little attention from the authorities who were directing weightier movements at the centre. Less formal than these, and more provocative of bitter feeling, were the attacks of guerrillas along the central frontier,--chiefly the Missouri border and eastern Kansas. Here the passions of the struggle for Kansas had not entirely cooled down, southern sympathizers were easily found, and communities divided among themselves were the more intense in their animosities. The Department of Kansas, where the most aggravated of these guerrilla conflicts occurred, was organized in November, 1861, under Major-general Hunter. From his headquarters at Leavenworth the commanding officer directed the affairs of Kansas, Nebraska, Dakota, Colorado, and "the Indian Territory west of Arkansas." The department was often shifted and reshaped to meet the needs of the frontier. A year later the Department of the Northwest was cut away from it, after the Sioux outbreak, its own name was changed to Missouri, and the states of Missouri and Arkansas were added to it. Still later it was modified again. But here throughout the war continued the troubles produced by the mixture of frontier and farm-lands, partisan whites and Indians.