One name, among those officers under whom John Jay Jackson served during and following the War of 1812, has provided me more resources than that of the others. That name was Charles Pentland.
Though he wasn't a captain to whom John Jackson reported, Charles Pentland's name was the one appearing on Jackson's near-destroyed discharge papers—in particular, the one to which the note was affixed in his pension file,
Hold this discharge up to the light and the genuine Signature of S. C. Pentland will be seen.
Pentland, serving as ensign in the 4th Rifles at about the time John Jackson enlisted in the army in 1814, was a Pennsylvania-born military man who rose in the ranks to first lieutenant at about the time John Jackson was eventually discharged from his post near Saint Louis in 1818.
Though he was present in the same company in which Jackson served for, likely, most of his service in the rifle regiment, that is not the main reason for my focus on him, today. Pentland's value—at least to our exploration of a fuller picture of the context in which Jackson served—was in his diligent journaling of the various military expeditions in which he was involved.
In tracing the whereabouts of Pentland—and thus, likely, of my husband's fourth great grandfather—his was the name most likely to come up in searches for the names of all Jackson's military leaders. More than Morris, more than "Birdsell," more than "Duffy" and more than McGonigle, with the exception of Captain Magee, the name I encountered the most in my searches was that of Pentland.
There is good reason for this. In all the far-ranging expeditions in which Pentland was involved—from Pittsburgh to Saint Louis to the outer reaches of the Missouri and associated rivers, in territory later to become the states of Nebraska and the Dakotas—he kept a journal.
His observations were perpetuated by means of copybooks, many of which in annotated form have found their way into the collections of various university archives. March of the Pittsburgh Blues Copybook now is a part of the holdings at the University of Pittsburgh, where it provides an excerpt from the Pentland journals detailing the length and destination of the unit's daily marches, brief accounts of battles and number of casualties incurred in the year beginning September 10, 1812.
Another resource extracted a brief schedule from Pentland's journal of that same year, giving an overview of the year's activities during the war.
Of course, that was before John Jackson's enlistment in the 4th Regiment of Riflemen, so it doesn't provide information pertinent to his own history. But it does give an idea of the daily routine Jackson was about to enter, as his service likely involved the same types of establishment or repair of forts along the tributaries of the upper Mississippi River.
Immediately after his discharge, Jackson's regiment continued that type of work in its assignment to establish a string of army fortifications along the Missouri River in such forays as the Yellowstone Expedition. Among other contemporaneous records, the orderly books of the Rifle Regiment provide excerpts of the events in the construction of Cantonment Missouri, the first of the projected outposts.
Likewise, the names of Jackson's former superiors Pentland and Magee once again began appearing in tandem in reports of expeditions contained in the journals of other military men. Often, I would find entries on their names inserted as footnotes in transcriptions of those journals. Those footnotes, in turn, invariably were lifted from Heitman's Historical Register and Dictionary of the United States Army.
Though again not directly involving John Jackson, these descriptions of the territory covered and the forts established during the expeditions were likely similar to the assignments in which Jackson engaged during his own tour of duty.
Two additional names often cropped up in addition to those of Magee and Pentland in such reports: that of Stephen Harriman Long and Stephen Watts Kearny. The Kearny journal has since been published, as well as reports of Long's expedition, in various excerpts.
In the fourth quarterly of the 1919 Nebraska History and Record of Pioneer Days, an article on "Three Military Heroes of Nebraska" explained the mission of one such expedition:
On the second of July, 1820, an exploring party started from Cantonment Missouri...to discover a route across country between that post and Fort Snelling.... The expedition proper comprised Captain Matthew J. Magee and First Lieutenant Charles Pentland of the Rifle Regiment....
The author of the article, Albert Watkins, explained that Captain Stephen Kearny accompanied the expedition but was not a part of it, noting
Probably because Captain Kearny kept a journal of the expedition, it has often been said that he led it.
The author also went on to surmise on the real goal of such army expeditions:
The fact that the route approximately paralleled the subsequent lines of railroads from Omaha to Saint Paul at no great distance from them, and that the captain pronounced the region through which it ran as incapable "of supporting more than a thinly scattered population," impeached his judgment, putting him in the same class with Major Long, who proved himself a false prophet in the same way and year.
Though Major Long had once dismissed the area of his exploration as the "Great Desert," and the originating Yellowstone Expedition—at least in a biographical sketch on its commander, Henry Atkinson—was intended by the government to be a warning to British traders and Indians in the upper Missouri country, records generated by these and related expeditions serve as the few windows allowing us to look upon the military service of our ancestors during those early American decades for which military documentation was not as readily available.
Above: Map of North America detailing the approximate area of the 1803-1804 Louisiana Purchase west of the Mississippi River, prepared for the American edition of Pinkerton's Atlas, published in Philadelphia in 1818 by Thomas Dobson & Company; courtesy Wikipedia; in the public domain.