Immigration within the American hemisphere remained uncapped until 1965 but in 1924 Congress authorized funding for the Border Patrol to regulate crossings occurring between immigration stations on both the northern and southern borders.
TITLE IV-DEPARTMENT OF LABOR
BUREAU OF IMMIGRATION
Regulating immigration : For enforcement of the laws regulating immigration of aliens into the United States, including the contract labor laws ; cost of reports of decisions of the Federal courts, and digests thereof, for the use of the Commissioner General of Immigration; salaries and expenses of all officers, clerks, and employees appointed to enforce said laws . . . all to be expended under the direction of the Secretary of Labor, $4,500,000: Provided, That at least $1,000,000 of this amount shall be expended for additional land-border patrol of which $100,000 shall be immediately available : Provided further : That the purchase, exchange, use, maintenance, and operation of horse and motor vehicles required in the enforcement of the immigration and Chinese exclusion laws outside of the District of Columbia may be contracted for and the cost thereof paid from the appropriation for the enforcement of those laws, under such terms and conditions as the Secretary of Labor may prescribe : Provided further, That not more than $50,000 of the sum appropriated herein may be expended in the purchase and maintenance of such motor vehicles: Provided further, That not more than $38,000 of this amount shall be expended in the purchase and maintenance of motor vehicles for additional land-border patrol.