Area and Population.— At the time of its first incorporation the city was confined to the small triangle at the confluence of the Mononga hela and Allegheny rivers, bounded on the east by Grant's Hill, so named after Major Grant of Forbes' army, who was defeated and lost his life in an encounter with the French, a few days before the capture of the spot by Forbes. The area of this site was only 320 acres, or less than half of a square mile. In 1909, at the time of the absorption of Beech view Borough, the latest addition to the city, its territory had expanded to 26,465 acres, or 41.35 square miles. The greatest territorial ad dition occurred on 30 June 1868, when six adja cent townships were annexed, they having an area of 13,568 acres. The greatest single in crement in the population was made when, on 7 Dec. 1907, the city of Allegheny, having more than 150,000 inhabitants, was merged into the city of Pittsburgh. The population ascertained by the United States census of 1910 was 533, 905; an estimate made by the Bureau of the United States census in July 1918 gave a popula tion of 596,303. This is, however, very far from truly representing the urban population found in the locality known as Pittsburgh. The city is growing and expanding on all sides beyond its comparatively narrow municipal limits and in the immediate suburbs there are almost as many people as within its legally defined bound aries. Within a radius of 10 miles of the tower of the Pittsburgh courthouse there are over a million of people and as a °Metropoli tan Centre," according to the last United States census, Pittsburgh holds the fifth place in the United States, being outranked by only New York, Chicago, Philadelphia and Boston, in the order given. As in all of the larger in dustrial centres of North America, the popula tion of Pittsburgh contains a very large per centage of the foreign-born, attracted to the spot by the opportunity to find remunerative employment. There are many Hungarians, Poles, Slovaks, and Ruthenians in Pittsburgh, and these are even exceeded in number by me Italians and Germans. There are in the neigh borhood of 10,000 Greeks in the city and a con siderable number of Belgians. The foreign element is largely drawn from those regions of the Old World in which mining and glass working prevail. Since 1914 there has been a large influx of negroes from the Southern States.
Transportation Facilities.— The three rivers which traverse the city are important waterways and provide within the limits of the city proper a water-frontage of more than 40 miles. The Monongahela by the construction of dams and locks has been made navigable for a distance of more than 100 miles to the south and access is thus gained to the im mense coal-fields of the northern part of West Virginia. The Allegheny is being canalized in the same way and thus the oil- and coal fields of the upper counties of western Pennsyl vania are being reached. By the Ohio the door is opened to thousands of miles of navigable water in the west and the south and access is had to the Gulf of Mexico and the oceans of the world. There is a large river traffic be tween Pittsburgh, Cincinnati, Saint Louis and New Orleans. In the early years of the last century, Pittsburgh was an important ship building centre and before the days of such gigantic craft, as now sail the seas, many wooden ships, which in those days were es teemed of large size, were built in Pittsburgh and, passing down to the Gulf, entered into maritime commerce. At so late a period as that of the Civil War, smaller vessels were con structed here and a number of the early °Mon itors," among them the Miantonomak and sister ships, were launched from Pittsburgh ways.
Even now the building of stern-wheel river boats and marine engines is an important in dustry and craft of this description built and engined in Pittsburgh are being constructed for use upon the rivers of both Americas, upon the Volga, the Danube, the Yangtse, and the Kongo. In quite recent years the construc tion of steel barges for the transportation of coal has become an industry of magnitude. The harbor of Pittsburgh by the erection of the Davis Island Dam on the Ohio River has been made navigable throughout the year and here assemble the great "coal-tows," which at times of flood descend the Ohio to the Missis sippi and go south to the Gulf. The word "tow" as applied to these assemblages of huge coal-laden barges is a misnomer, though in constant use. The barges are assembled in front of the propelling craft, a stern-wheel steamboat, and are pushed rather than "towed" along their course.
The facilities for transportation by water have been during the past 70 years enormously supplemented by the construction of railways. At the present time there are 14 different steam railways entering the city, connecting with all the railway systems of the country. The loca tion of Pittsburgh as a point for the assem blage and distribution of merchandise is thus very favorable and the city is within one night's ride of half the population of the United States at the present time. Its central position is shown by the following scale of distances: to Wheeling 67 miles; to Cleveland 150 miles; to Buffalo 270 miles; to Washington 290 miles; to Baltimore 334 miles; to Philadelphia 340 miles; to New York 431 miles; to Chicago 468 miles. By express trains the most distant of these points is reached in less than 12 hours.
Travel within the city and the adjacent sub urbs is facilitated by lines of electric railways radiating in every direction and extending far through western Pennsylvania, West Virginia and eastern Ohio. There are in the city 772 miles of streets and boulevards and 335 miles of ways and alleys under 20 feet in width, or a total of 1,107 miles of The boulevards are kept free from rails and are the main arteries of communication by automo bile. Owing to the peculiar topography, Pitts burgh has probably more bridges and viaducts than any other city in the world. There are 114 bridges and viaducts within the city proper, not counting railway bridges, of which there are seven. Almost every style of construction known to the engineering profession is repre sented by them. The Bloomfield bridge, con necting the Herron Hill district with the Bloom field district, spans a deep valley and has a length of 4,962 feet, 6 inches. The Manchester bridge, spanning the Allegheny at its confluence with the Ohio, has a length of 3,257 feet. The Larimer Avenue viaduct at the time it was built was the longest single arch of reinforced concrete in the world, having a span of 312 feet, at its centre 125 feet above the bottom of the ravine which it crosses. Since it was built one or two others of larger span have been con structed, one of these in Australia. One of the interesting means of communication between certain parts of the city which excites the curi osity of visitors are the inclined planes, built to carry passengers and vehicles. There are a number of these, which enable a quick ascent to be made from lower to higher levels, with out long detours. One of the best known of these is the Mount Washington Incline, opposite the Pittsburgh and Lake Erie Railroad station, by which in a minute the passenger is lifted 400 feet above the level of the old city and finds himself in a city literally "set upon a hill," looking down upon the steeples and "sky-scrap ers" far below.