I-5 enters the city of Elk Grove while passing along the eastern edge of the Stone Lakes National Wildlife Refuge. It then crosses into the Sacramento city limits, soon paralleling the Sacramento River before intersecting the Capital City Freeway, which carries US 50 and I-80 Business (I-80 Bus.). SR 99 merges with I-5 at this point, and the two routes pass through the western half of downtown Sacramento. Following the bridge over the American River, I-5 and SR 99 intersect the major transcontinental route of I-80. Just as I-5 leaves Sacramento, SR 99 splits off and continues north while I-5 turns due west past Sacramento International Airport and crosses the Sacramento River into Yolo County. In Woodland, the SR 113 freeway merges with I-5 before exiting to the north. The Interstate heads northwest again toward Dunnigan, where it converges with I-505.