Owing to the mountainous character of the country, the city is exceedingly irregular in shape and its suburbs are widely separated from each other. The city proper lies between Castle, S. Antonio and Santa Thereza hills on the south, and S. Bento, Conceicao and Livramento hills on the north, spreading out to the westward over an extensive low plain. The suburbs of Cattete, Laranjeiras, Botafogo and Gavéa lie to the south-west and comprise some of the most picturesque and salubrious localities in the city. The Cidade Nova, S. Christovao, Engenho Novo, Villa Isabel. Tijiuca and other smaller suburbs lie to the west and north-west. There are but few wide streets in the old town, and the majority of sums the buildings are of the old style, built principally of broken stone and mortar, plastered on the outside, or faced with illuminated tiles.

The size, climate and hygienic conditions of the population of the city, being somewhat similar to New Orleans, the growth of the latter from 1870 to 1880 may be taken as a fair basis upon which to calculate the present (December, 1886) population of Rio de Janeiro. The increase of population in New Orleans was very nearly 13 per cent between 1870 and 1880, or an average increase of 1.3 per cent per annum. For the 14 years since 1872 this rate gives an increase of 50,000, from which the present population appears to be about 325,000. A local statistician, Sr. J. P. Favilla Nunes, estimates the total population for 1885 however, at 357,332. For the 14 years under consideration the average annual death rate was over 35 per thousand, the immigration small and the conditions of life somewhat unfavorable to a large increase of population; this assumption of the New Orleans rate of increase may therefore be accepted as a fair and favorable basis for Rio de janeiro. According to the last official reports the total number of buildings, both public and private, in the city and its suburbs was 33,327, of which over 2,000 were reported as unoccupied.

The city possesses 1,045 streets and alleys of all descriptions, 77 public squares and gardens, 7 cemeteries, 67 churches and 10 hospitals the mountain sides of the Corcovado and the hills extending back toward Tijuca.