Saint John, a river of North America, called by the Indians Looshtook (Long river), which rises, under the name of the S. W. branch, in the highlands that separate Maine from Quebec, Canada, at the Metjarmette portage. It flows N. E. to the junction of the St. Francis, about 150 m., for 100 m. of which, commencing at the junction of the N. W. branch, it is known as the Walloostook. From the mouth of the St. Francis it flows E. N. E. and then S. E. to the Grand falls, where it has a perpendicular descent of 70 or 80 ft., thence nearly S. to lat. 46°, when it turns suddenly and flows E. for 100 m. to the entrance of the outlet of Grand lake, thence in a broad channel due S. to Kingston, then S. S. W. to West-field, and finally S. E. to the bay of Fundy at St. John. Its whole course is about 450 m.; of this 225 m. of the lower portion is wholly within British territory; 75 m. from the Grand falls to the St. Francis forms the boundary between Maine and New Brunswick; the next 112 m. is in Maine; and from its source to lat. 46° 25' N., lon. 70° 4' W., 38 m., it forms the boundary between Maine and Quebec. It has 11 principal affluents, the largest being the Alleguash, St. Francis, Madawaska, and Aroostook. It is navigable for vessels of 120 tons to Fredericton, 84 m. from its mouth; small steamboats ascend to Woodstock, 75 m. further, and even at times to the Grand falls, 225 m. from its mouth; above this point it is navigated by steamboats 40 m., to the mouth of the Madawaska. It affords a vast water power.
With its branches it furnishes 1,300 m. of navigable waters, and drains 17,000,000 acres, of which 9,000,000 are in New Brunswick, 2,000,000 in Quebec, and 6,000,000 in Maine.
Saint John, a S. county of New Brunswick, Canada, bordering on the bay of Fundy, and intersected by the St. John river; area, 585 sq. m.; pop. in 1871, 52,120, of whom 30,128 were of Irish, 13,772 of English, 5,785 of Scotch, 739 of German, 616 of African, 37T of Dutch, and 340 of French origin or descent. The surface is agreeably diversified and the soil fertile. The European and North American and the Intercolonial railways traverse the county. Capital, St. John.