SHENANDOAH, river of the United States in Virginia, rising at N. Lat. 56', in the extreme southern angle of Augusta county. The various sources, however, spread over, and drain the far greater part of Augusta and Rockingham counties. In the latter rises also a large though secondary branch, the North-Fork. Both streams issue sepa rately from Rockingham, and flowing nearly parallel to each other, in a north-east direction, over Shenan doah county, the North Fork inflects to the east and joins the main stream near the south-east border of Frederick county. At their junction the Shenandoah has flown by comparative courses about 90, and the North Fork 60 miles. Now a line mountain river, the Shenandoah, continues its direction to the north east 40 miles, over Frederick and Jefferson counties, to its final influx into the Potomac, at Harper's Ferry, 18' N., having traversed 82' of latitude. The level of Shenandoah aml Potomac, at Harper's Perry, is 182 feet above tide water in the latter; and compar ing the sources of the former with those of James river, the elevation of their dividing ground must be at least 2,000 feet above the Atlantic tides; therefore, in a course of 82 minutes of latitude, the Shenandoah falls Upwards of eightf_en hundred feet.
This river and its branches flow from the fine val ley between the Blue Ridge and Kittatinny mountain; the sources of the main stream in its entire course draining the north-west slopes of the former moun tain. The Shenandoah valley in particular, comprises
an area of very nearly 2500 square miles, and by the census of 1820, it then sustained a population of nearly 80,00,0 inhabitants, or 32 to the square; exceed ing the general distributive population of Virginia 16 to 9. Occupying a part of the great limestone region stretching along the northwest base of the Blue Ridge, the Shenandoah valley is a grain and fruit producing country, and in a state of very rapid improvement. The climate it must be evident from its northern slope, is, in respect to temperature, in verse to the latitude. The sources in Augusta, ele vated 1800 feet above the mouth, must influence the temperature equal to at least 4 degrees of latitude. Rising therefore from I larper's Ferry, though the ad vance is southward and length of the valley only 82 minutes of latitude, the seasons of spring, harvest, and autumn, and even winter, evince a change from a milder to a colder temperature, amounting to an equivalent to or 3 degrees of latitude.