I-40 goes from Wilmington, NC
to Barstow, CA
, about 100 miles NE of Los Angeles. To get from Barstow to Los Angeles, take I-15 to Route 210 to I-610. I-10 goes from Jacksonville to LA
though, and I-80 goes from just outside NYC (starts in Fort Lee pretty much, which is where the GWB is...I-80 branches off of I-95), and goes to San Francisco. The other trans-con freeway is I-90, from Boston to Seattle.