There are a total of 500 agility orbs that are scattered across Pacific City. Running around the city is a easy way to obtain orbs. Once you reach the 400+ point, grab a helicopter and click down the to turbo speed. This will make your mini map a very large area and just start pinging () to see if any orbs are around. You can always check your progress in a certain area by going (start) > Achievements > and scroll to find "King of the World."
These are the total orbs for each area (500 total):
- Hope Springs - 231
- Green Bay - 140
- Unity Heights - 115
- Agency Island - 14
If you need help, use this interactive map: Agility Orb Interactive Map