Pike's military career included working on logistics and payroll at a series of frontier posts, including
Fort Belle Fontaine near today's
St. Louis.
General-in-Chief James Wilkinson of the
United States Army was appointed as the first Governor of the Upper
Louisiana Territory by third President
Thomas Jefferson, becoming Pike's mentor while headquartered there. In 1796, Pike shadowed the expedition of General
Georges Henri Victor Collot, a Royal, then Imperial
French Army officer who had been tasked to tour the Mississippi frontier and draw maps that France might use if it were to try and seize the lightly settled heartland territory of the Mississippi River valley basin from the nascent United States further to the East. Beginning July 15, 1806, Pike led what became known as the "
Pike Expedition". In early November 1806, Pike and his team sighted and tried to climb to the summit of the peak later named after him (
Pikes Peak). They made it as far as Mt. Rosa, located southeast of Pikes Peak, before giving up the ascent in waist-deep snow. They had already gone almost two days without food. They then continued south, searching for the Red River of the South's headwaters, and
built a fort for shelter during the winter. However, they had crossed the border, whether through confusion or deliberation. Royal Spanish authorities captured Pike and some of his party on February 26, 1807. Pike and his men were taken to the old colonial capital of
Santa Fe of the Royal Spanish province of
New Mexico and on further south to the
Chihuahua City capital of
Chihuahua province, and presented to
Commandant General Salcedo, who was governor of the state. Pike was treated well and invited to formal social dinners but still not quite given the treatment of a visiting diplomatic dignitary, and his men were kept prisoner. Salcedo housed Pike with Juan Pedro Walker, a cartographer who also acted as an interpreter. Walker transcribed and translated Pike's confiscated documents, including his journal. Spanish authorities feared the spread of both their democracy and
Protestant Christian sects that might undermine their rule. During this time, Pike had access to various maps of the southwest and
New Spain, and especially learned about colonial Mexico's increasing discontentment with Royal Spanish rule. Spain filed official protests with the United States about Pike's exploring expedition, but since the nations were not at war (and the Kingdom of Spain was rebelling against
Napoleon Bonaparte's older brother, who was put in place to rule Spain and was also fighting
Great Britain in the
Peninsular War), Commandant Salcedo released the American military men. The Spanish escorted Pike and most of his men back north, releasing them at the Louisiana border on July 1, 1807.
War of 1812 Pike was promoted to the rank of
captain during the southwestern expedition. In 1811, Pike fought with the 4th Infantry Regiment at the
Battle of Tippecanoe under General (and future ninth President)
William Henry Harrison. He was promoted to colonel of the 15th Infantry Regiment in July 1812. Pike's military career also included service as deputy
quartermaster-general in
New Orleans and
inspector general during the later part of the
War of 1812. Pike commanded the advance guard of an American force which was defeated—primarily because of the poor planning and half-hearted effort of his commander,
Henry Dearborn—at the first
Battle of Lacolle Mills in November 1812. Pike was promoted to brigadier general in March 1813. Along with General
Jacob Brown, Pike departed from the newly fortified rural military outpost of
Sackets Harbor, on the
New York shore of
Lake Ontario, for what became his last military campaign. On this expedition, Pike commanded combat troops in the
successful attack on York (now
Toronto) on April 27, 1813. Pike was mortally wounded and died, along with numerous other American troops, by flying rocks and other debris when the withdrawing British garrison blew up its ammunition magazine as Pike's troops approached
Fort York. His body was brought by ship back to Sackets Harbor, where his remains were buried at the
Military Cemetery. ==Confiscated papers==