FamilySearch database of the 1880 Census, Milroy, Grant, WV, PORTER:
Hiram W., 49; wf. Elisabeth, 49; dau. Hannah C., 22 (all births so far in Virginia); ch. b. WV: Isaac L., 17; Hiram F., 15; Mary A., 12; & Rebecca J., 10.
John, 24; wf. Susan, 24; dau. Hannah S. E., 2 mos.
George, 19; wf. Mary J., 22.
SEAR, John T., 49, VA VA VA; wf. Maranda, 49 (she & parents b. MD); ch. b. VA: Susan P., 22; Ann E., 20; Peter L., 19; b. WV: Perry H., 16; Lillie, 11; Ellie M. & Corra A., both 9.
In Grant, Grant Co., WV, PORTER: Clarence, 21, farm laborer for A. W. SEYMOUR.
RootsWeb Family Trees: George L. PORTER (1810, VA - before 1870, Pendleton Co., WV) m. 5 Nov. 1829, Pendleton Co., [W]VA, Sarah TINGLER, b. 1812. Children, probably b. Pendleton Co.:
Hiram (ca. 1830/1 - 15 Sep. 1900, Falls, WV) m. 12 D 1853, Elizabeth SHIRLEY.
Susan Jane (4 Aug. 1831? - 1 May 1926, bu. Mallow Cem., Upper Timber Ridge) m. 23 Aug. 1851,
Isaac J. NELSON, b. 1827, VA.
Mary, b. ca. 1833/4
Emma Jane (24 Feb. 1836 - 1900+) m1. 20 Aug. 1857, Sampson PENNINGTON, b. 1832; m2. 7 Je. 1870, Jesse HINKLE.
Isaac V., b. 18 July 1839
Elizabeth V., ca. 1841
Sidney Dean (14 Je. 1843 - 1920+) m1. ca. 1860, Elijah Stewart NELSON, b. 1846; m2. Lafayette ELZA; m3. Jonathan Clark ARBAUGH.
Sarah E., b. 1852.
Considering a marriage date late in 1853, the PORTER families of Grant County in 1880 were likely Hiram and his sons. Censuses from 1860 & 1870 should help. Grant adjoins Pendleton Co., WV, on the northeast. Hardy Co. is east, just across from Shenandoah Co., VA. Note that the family didn't necessarily move, the change from VA to WV on the births occurs when the state was formed.
--My line is from Peter PORTER, listed in Peter W. COLDHAM's Complete Book of Emigrants, 1607 -1660: At the Eastern Shore, [VA], Petter PORTER, 1624; & at Elizabeth City, 1625, Peeter PORTER, 20, [came on] the Tiger, 1621. There's a book on Peter's family, but the first generations are sketchy.