When it opened to guests on July 17 , 1955 , the property consisted of Disneyland , its 100-acre ( 40 ha ) parking lot , and the Disneyland Hotel , owned and operated by Disney 's business partner Jack Wrather .
When it opened to guests in 1955 , the property consisted of Disneyland , its 100-acre ( 0.40 km2 ) parking lot , and a hotel known as the Disneyland Hotel , owned and operated by Disney 's business partner Jack Wrather .