Reference L. W. Jackman, Genealogist, 206 Bentley Street, Knoxville, Tennessee 4-1937
By reference of Vol. XII, page 111 and Vol. II, series, VI, page 199 and 164 of the Pennsylvania Archives, it will be found that Robert Jackman and his sons Edward, John, Robert II and William all served as soldiers in the Revolutionary War from Washington County, Pennsylvania. Robert as Captain, John, Robert II and William as petty officers and Edward served as a private. All of them served under Colonel Thos Crook in the defense of the Western Frontier.
( I could not provide evidence that there is a Robert Senior and a Robert II, both serving in the Revolutionary War.Here is the following information that I gathered:
Pennsylvania Archives Series 7, Volume III, Index to 6th Series, page 1579
Jackman, Robert 6th S, II, 199 (used as reference for Robert II by someone)
Jackman, Robt., 6th S, II, 209 (used as reference for Robert II by someone), IV 325
Pennsylvania Archives Series 3, Volume XXVIII, Chapter, General Index to Volumes XI-XXVI, page 777
Jackman, Robert XXII, 732; xxvi, 671 (XXII is Supply Tax List ) (XXVI (Land Warrent List)
Pennsylvania Archives, Series 3, Volume XXII Chapter: Effective Supply Tax for the County of Washington 1781, page 732.
Jackman, Robert 613 acres, 3 horses, 8 cattle, 12 sheep, Value 730
Pennsylvania Archives Series 3, Volume XXVI Chapter: PRovidincial Papers: Warrantees of Land in the Several Counties of the State of Pennsylvania 1730-1898 Page: 571
Jackman, Robert 322 1/2 acres Feb. 22, 1785
Jackman, Robert 223 3/8 acres Feb. 22, 1785
Pennsylvania Archives, Series 1, Volume X, Pennsylvania Archives 1784, page 289
8th Company
Robert Jackman, Capt. (No. of Men: 68)
Pennsylvania Archives, Series 6, Volume II, Fifth Battalion, Washington County, Militia, page 189
5th Battalion
Lt. Colonel John Guthridge, Major James Craven
Robert Jackman, nominated Captain 68 men
1800 U.S. Federal Census, Pike Run Township, Washington County, Pennsylvania
Jackman Robert 3 males under 10, 2 males 10 to 15, 1 male 16 to 26, 1 male 45 to etc;
Jackman Robert 1 male under 10, 1 male 26 to 44 etc;
County Census of Taxables, page 57 Ancestry.com
Jackman Henry Sr.
Jackman Wm
Robt. Sr.
Jackman Wm (Piker
Jackman Robert Jr. Miller
List of Inhabitants in Washington County, Pennsylvania 100 or before, page 15 Ancestry.com
Jackman, Edward, John, Richard, Richard Jr., Robert, Robert, William
DAR Patriot List A060849
Robert Jackman, CAptain Pennsylvania Birth 4---1739 Ireland, Death 26 Aug 1813, Washington Co. PA, PA Arch 6th Ser. Vol. 2 P 199-109, Also Pvt. Washington Co. Militia
Pennsylvania Archives, Executive Minutes of Governor Thomas Mifflin, 1792-1794, page 686
Fourth Regiment
Ensign Robt. Jackman
Robert Jackman moved to Washington County, Pennsylvania, during the year 1773 and he and his sons, Edward, John, Robert II and William all took up claimsin that county as shown in the third servies of the Pennsylvania Archives, Vol. 22, page 732.
Edward Jackman b. 1735 married Barnett and had sons Robert III, William, Allen, Atwell, Richard and Barnett. During the latter decade of 1700 he and his sons moved from Washington County, Pennsylvania to the valley of the White Water River in SouthWestern Ohio and settled about four miles south of Harrison Ohio. Several members of this fammily still remain in that vicinity while others are to be found about Andersonville and Milroy Indiana. Richard Jackman left here sometime before 1799 and went to Vincennes, Indiana where on January 6. 1799 he married hte daughter of Allen Ramsey.