The Dominican Republic has twelve ports of entry, but nine-tenths of the foreign commerce goes through the ports of Macoris, Santo Domingo, Sanchez and Puerto Plata. The first two supply the import and export requirements of the southern portion of the Republic, the other two those of the Cibao. The other eight custom-houses exist for local convenience and for the prevention of smuggling. This is especially true of the three along the Haitian frontier. In former years there was considerable smuggling across the border, as the import duties on certain articles in Haiti are much lower than in the Dominican Republic. Although the profitable smuggling business demoralized trade in those regions, the government did not interfere with it owing to the difficulty of policing the wild and sparsely populated border district. The American general receiver determined that the back door should be guarded as well as the front entrance, and formed a frontier guard which stopped contraband traffic, though at a heavy cost, for two brave American officials have been killed and three wounded by smugglers and outlaws, while fourteen Dominican guardsmen and inspectors have been killed and twenty-three wounded. The expense of the three frontier custom-houses is greater than the revenue they produce, but entries in Azua, Monte Cristi and Puerto Plata increased significantly after the frontier guard began its patrolling. Incidentally the guard has helped to keep the boundary line in place.
In the seaports most of the loading and unloading is done by lighters, the wharves generally being small affairs. Only in Puerto Plata (where extensive harbor improvements are now under way), Macoris and Santo Domingo can larger vessels approach the wharves. All the wharves were built under concessions from the government, which, in the impossibility to provide them itself on account of its perpetual lack of funds, was obliged to procure their construction by granting the right to collect a specified wharf tax, more or less onerous, for a period of years. The Santo Domingo City wharf concession provided that everything exported from and imported into this city or any other coast point in the province must pay the tax, whether the wharf was used or not. The Samana wharf concession; as amended, gave the right to collect certain high wharf taxes for fifty years, from 1875 to 1925, in return for the building of a diminutive dock. One of the important objects accomplished through the 1907 bond issue was the redemption by the government of the monopolistic wharf concessions.