 With most work finished on the dam itself ( the powerhouse remained uncompleted ) , a formal dedication ceremony was arranged for September 30 , 1935 , to coincide with a western tour being made by President Franklin D. Roosevelt . The morning of the dedication , it was moved forward three hours from 2 p.m. Pacific time to 11 a.m. ; this was done because Secretary of the Interior Harold L. Ickes had reserved a radio slot for the President for 2 p.m. but officials did not realize until the day of the ceremony that the slot was for 2 p.m. Eastern Time . Despite the change in the ceremony time , and temperatures of 102 ° F ( 39 ° C ) , 10 @,@ 000 people were present for the President 's speech in which he avoided mentioning the name of former President Hoover , who was not invited to the ceremony . To mark the occasion , a three @-@ cent stamp was issued by the United States Post Office Department — bearing the name " Boulder Dam " , the official name of the dam between 1933 and 1947 . After the ceremony , Roosevelt made the first visit by any American president to Las Vegas . 
 With most work finished on the dam itself ( the powerhouse remained uncompleted ) , a formal dedication ceremony was arranged for September 30 , 1935 , to coincide with a western tour being made by President Franklin D. Roosevelt . The morning of the dedication , it was moved forward three hours from 2 p.m. Pacific time to 11 a.m. ; this was done because Secretary of the Interior Harold L. Ickes <a href='been_done' title='1'><mark>had</mark></a> reserved a radio slot for the President for 2 p.m. but officials did not realize until <a href='None' title='2'><mark>the</mark></a><a href='negative_concord' title='3'><mark>day</mark></a> of the ceremony that the slot was for 2 p.m. Eastern Time . Despite the change in the ceremony time , and temperatures of 102 ° F ( 39 ° C ) , 10 @,@ 000 people <a href='uninflect' title='4'><mark>were</mark></a> present for the President <a href='null_genetive' title='5'><mark>'s</mark></a>speech in which he avoided mentioning the name of former President Hoover , <a href='null_relcl' title='6'><mark>who</mark></a>was not invited to <a href='None' title='7'><mark>the</mark></a><a href='negative_concord' title='8'><mark>ceremony</mark></a> . To mark the occasion , a three @-@ cent stamp was issued by the United States Post Office Department — bearing the name " Boulder Dam " , the official name of the dam between 1933 and 1947 . After the ceremony , Roosevelt made the first visit by any American president to Las Vegas . 
With most wrk finished on the dam itself ( da powerhouse remained uncompleted ) , a formal dedication ceremony was arranged for September 30 , 1935 , to coincide with a western tour bein made by President Franklin D. Roosevelt . The morning of tdadedication , it was moved forward three hrs from 2 p.m. Pacific time to 11 a.m. ; this was done because Secretary of thdanterior Harold L. Ickes done reserved a radio slot for thedaesident fir 2 p.m. but officials did not realize until no day of the ceremony dat the dat was fir 2 p.m. Eastern Time . Despite the change in the ceremony time , and temperatures of 102 ° fuc ( 39 ° C ) , 10 @,@ 000 folks was present for the President  speech in which he avoided mentioning the name of former President Hoover , was not invited to no ceremony . To mark the occasion , a three @-@ cent stamp was issued by the United States Post Office Department — bearing the nda " Boulder Dam " , the official name of the dadaetween 1933 and 1947 . After the cerdany , Roosevelt made the first visit by any American president to Las Vegas .