http://www.nps.gov/vafo/historyculture/johnfitzgerald.htm
Lt Col John Fitzgerald
In 1769, John Fitzgerald emigrated from Ireland and later ran a mercantile business in Alexandria. He was a major in the 3rd Virginia Regiment in 1776, and he joined Washington's staff as an aide-de-camp in November of that year. Fitzgerald was on the battlefield at Princeton, and he is probably the source of the often-told story when covered his eyes as the British fire a volley at Washington, after which the commander-in-chief remains unscathed. During the Valley Forge encampment, Fitzgerald was sent to Virginia with a packet of letters, and he does not return until May. He was therefore absent from the army and headquarters for several months. Fitzgerald was wounded at the battle of Monmouth, and he resigned from the army shortly thereafter. He returned to his business in Alexandria, and at one point he helped supply American prisoners-of-war. Elected mayor of Alexandria in 1783, Fitzgerald's friendship with Washington continued after the war, when he was a guest at Mount Vernon. During Washington's presidency, he was appointed a local collector of customs. Fitzgerald declared bankruptcy in 1799 and died shortly thereafter. Washington wrote of Fitzgerald: "I shall now proceed to mention a person in whose skill and integrity … I have the fullest confidence; a Gentleman who is a native of Ireland – Colo. John Fitzgerald. The active Services of this Gentleman during the War, his long residence in the Country and intermarriage in it (with one of the most respectable families, Digges of Maryland) all entitle him to be considered as an American. The laws of this Country know no difference between him and a native of America."

1774 Fitzgerald and fellow Irishman Valentine Peers become partners in the linen trade in the mid-1770s. They may be receiving their goods at the public wharves or on the dedicated half of Carlyle and Dalton's wharf at Cameron St.
1776 With the outbreak of the Revolutionary War, both join the Continental Army, Fitzgerald becoming a colonel, General Washington's aide-de-camp and his lifelong friend. Peers is discharged in 1777. Fitzgerald continues at Washington's side.
1778 April 27, Patterson's widow and son sell the two lots to Fitzgerald (on leave from Valley Forge) and Peers, for 1,400 pounds.7 In September, the two are granted rights by the town to the mudflats running into the Potomac.8

We have no portrait of him and no birthdate for him, but we do know that John Fitzgerald projected leadership.
Within a year of his arrival in Virginia, he is elected to the House of Burgesses. In the spring of 1776, he is commissioned captain in the Third Virginia Regiment and by fall he is a colonel in the Colonial Army. During the war, he exposes a cabal against Washington and gives early evidence against Benedict Arnold.
There is a diary attributed to Fitzgerald, describing Washington's soldiers with rags wrapped about their feet crossing the Delaware in snow and sleet to confront the Hessians in a surprise attack on Christmas 1776.16 The document is now considered "doubtful."17

In 1785, he is elected a director of the Potowmack Company formed to build a canal to deliver coal and other products from the Ohio Valley. The following year he is mayor of Alexandria.

In 1787, he buys a distillery on Wolfe Street at the river. He invests in lands from the Chesapeake to the Ohio. He acquires a country seat, "Federal Spring," just outside town. (His "counting house" on Fairfax and King is plaqued inaccurately as his residence.)

The 1780s initiate a period of brick warehouse construction. Another survivor, just a block away, is the Benjamin Shreve and James Lawrason warehouse on the southwest corner of Prince and Union streets, now a residence.

It is a grand military funeral. The coffin, followed by the colonel's riderless horse, is carried from his house on Duke Street (in 2006, a parking lot for St. Mary's Church) to his wharf and then by water to the Digges family plot at Warburton, Maryland. The order of procession is:
Times and District of Columbia Advertiser, Dec. 5, 1799
at 4 o'clock, the time of his interment at WARBURTON, 16 guns were fired from the point by Captain Harper's company of Artillery.

Two mysteries remain: the present site of Fitzgerald's grave and the fact that Washington does not mention his old friend's death in his diary; nor is there any record of his presence at the funeral.

http://www.hmdb.org/marker.asp?marker=8475
First Catholic Church in Virginia
A. D. 1795
Inscription. This stone taken from the canal of the Potomac Company of which Washington and Fitzgerald were Directors commemorates the erection of the First Catholic Church in Virginia, A. D. 1795, which stood until 1839 about twenty feet behind this marker.

In grateful acknowledgement of their aid in establishing this church the three trees to the north of this stone have been dedicated as follows to General George Washington as subscriber to the building, Colonel John Fitzerald, his favorite Aide de Camp, as the collector of the building fund,
Colonel Robert Hooe, Mayor of Alexandria, as the donor of the acre of land.

In commemoration of the bicentennial of the birth of George Washington this tablet was donated by the Holy Name Society of Sacred Heart Church (Vailsburg), Newark, N.J. on the 135rd anniversary of the funeral of Colonel John Fitzgerald, December 4, 1932.

"St. Mary's was established in 1795, and is the oldest Catholic parish in the Commonwealth of Virginia. To fund the church, Colonel John Fitzgerald, friend of George Washington and an early mayor of Alexandria, took up a collection. According to local tradition, Washington himself made the first donation. A chapel was built at the south end of the city, on land still used today as St. Mary's Cemetery." (Submitted on June 21, 2008.)
Excerpt from Robert Madison's book, Walking with Washington. "George Washington's diary shows that he and [John] Fitzgerald met together frequently. Fitzgerald's home was on the southeast corner of King and Fairfax Streets where the Burke & Herbert Bank is today. Since there was no Catholic church in Alexandria at that time, services were sometimes held in Fitzgerald's home. According to tradition, while dining there on Saint Patrick's Day in 1788, George Washington contributed to a fund to build Alexandria's first Catholic Church." (Submitted on June 21, 2008.)

The next time you are drinking coffee at Starbucks on the southeast corner of King and Union Streets, look around. You are in an eighteenth-century warehouse built by John Fitzgerald. A former aide-de-camp to General George Washington, John Fitzgerald (d. 1799) moved to Alexandria in 1769 and returned after spending the winter at Valley Forge. He purchased the south side of the 200 block of King Street with
Valentine Peers, and the town trustees granted them the "sunken ground" on the south side of King Street east of Lee Street in September 1778. They filled in the area east of Lee Street, and this building was John Fitzgerald's warehouse. It is typical of the Alexandria waterfront in George Washington's day. Fitzgerald was Alexandria's leading Catholic layman, one of the first directors of the Potomac Company and its president from 1793 to 1796, mayor from 1786 to 1787, a member of the Alexandria committee to ratify the U.S. Constitution in 1788, commander of the Alexandria Independent Dragoons, a founder of the Bank of Alexandria in 1792 and the Alexandria Library in 1794, and collector of the port. In his 1793 letter appointing Fitzgerald Collector of Customs of the Port of Alexandria, President Washington slipped from his general policy of not taking personal advantage of his public position and wrote "I am now about [to] give you a little trouble on my private account." The President wanted Fitzgerald's help in selling flour and tobacco that he had stored in Alexandria warehouses.

George Washington's diary shows that he and Fitzgerald met together frequently. Fitzgerald's home was on the southeast corner of King and Fairfax Streets where the Burke & Herbert Bank is today. Since there was no Catholic church in Alexandria at that time, services were sometimes held in Fitzgerald's home. According to tradition, while dining there on Saint Patrick's Day in 1788, George Washington contributed to a fund to build Alexandria's first Catholic Church. St. Mary's is the oldest Catholic parish in Virginia.
To learn more about the Fitzgerald Warehouse, read Diane Riker's "The Fitzgerald Warehouse" in the Summer 2007 issue of the Alexandria Chronicle at:

Catholics and the American revolution, Volume 2
By Martin Ignatius Joseph Griffin

http://etext.virginia.edu/etcbin/toccer-new2?id=WasFi37.xml&images=images/modeng&data=/texts/english/modeng/parsed&tag=public∂=221&division=div1
*To JOHN FITZGERALD
Mount Vernon, July 27, 1799.
Dear Sir: Recollecting that you had some doubt, At the last General Meeting of the Potomack Company, concerning the validity of your Powers to represent the state of Virginia in its interest therein, I wish to know whether those doubts have been removed by the Treasurer now in Office.
The Stockholders are called upon, I perceive by a Printed (and I presume circular) letter in precise terms to attend the next Genl Meeting in George Town the 5th. of next month, to consider, and decide on an important measure. Much is it to be regretted, that a work of such public utility and (if executed) of such immense advantage to the Undertakes, should be forced to go limpingly on as that has done; particularly to the injury of those individuals who (in affecting [illegible] red to promote the completion of it.
If you have not powers of sufficient validity to justify your voting on this occasion, I hope, to your [illegible] they will be given before the meeting; and if they are sufficient let me pray you to attend, and in time, for it is really necessary as well for the reputation as interest of the Company that the business should be rescued from its present Sloth.
I shall make a point of it, to be at the Union Tavern in George Town on the day appointed and by 11 oclock unless prevented by sickness; and in that case shall appear by Proxy; and I shall feel much chagreen if the State of Virginia is unrepresented thereat. With great esteem and regard I am etc.
[N.Y.P.L.]

http://www.pbs.org/georgewashington/collection/pre-pres_1785jul23.html
TRANSCRIPT GLC 3818 George Washington. Autograph letter signed: Mount Vernon, to Colonel John Fitzgerald, 1785 July 23. 1 p. + address leaf. Mount Vernon July 23d. 1785. Dear Sir, If there is any ship in the Port of Alexandria by which the enclosed Letters could receive a proper conveyance, you would much oblige me by giving them a passage. If not, by returning them. If I do not hear from my Lawyer in the Western Country before the first of August, it will be out of my power to proceed with the Directors (from the General meeting) to the Survey of the River. If my Suit should come to a hearing at the September term, w[hi]ch he thought highly probably, occurrances, of which he is to advise me, may indispensably call for my attendance [inserted: at the Tryal]. To perform both journeys, I canno nor would it be prudent for me, to pu it out of my power, by absence on th one, to avoid the other; as the decision of the Court may make a difference of between £3500 and £4000 [inserted: to me] for which I can sell the Land [inserted: in dispute] if I establish my right to it; of which there can be no doubt, if justice prevails, and the title is as clearly delineated as the case will admit of. I mention this matter in time, from a hope, that similar causes may not [inserted: interfere to] produce the same effect in any other of the Directors. With great esteem and regard I am – D[ea]r Sir Y[ou]r obed[ien]t friend and Affect[ionat]e Serv[an]t Go: Washington Notes: Unpublished. John Fitzgerald served in middle colonies (1776-1778) under Washington. In 1778 at the battle of Monmouth, Fitzgerald was wounded while carrying urgent messages from Washington to Charles Lee. In Alexandria, Virginia, Fitzgerald was associated with Washington in Potomac in promoting the Navigation Company.