Which cities are best for trick-or-treating?

For kids, Halloween is serious business.

The goal is to hit up as many homes in the shortest amount of time and bring back that big bag of Snickers, Twix, Starburst and whatever else people dished out.

Zillow unveiled its annual Trick-or-Treat Index that lists the top 20 cities where kids can get the most bang--candy that is--for their walk as they carry along their broomsticks, candy buckets and of course, their parents.

Ranking in the top spot for the third year in a row is San Francisco, which sports a very walkable city with safe areas. San Francisco also has the smallest percentage of children of any major cities in the nation, meaning more candy per little trick-or-treater. Boston ranked second followed by Honolulu. Washington, D.C., Minneapolis, Denver, Buffalo and Cincinnati also made the Top 20 list.

How did Zillow calculate the best trick-or-treating cities? The folks used four key variables: Zillow Home Value Index, population density, Walk Score® and local crime data from Relocation Essentials. These factors helped determine the cities that will provide the most candy, with the fewest walking and safety risks.

20 Top Cities for Trick-or-Treating

1. San Francisco

2. Boston

3. Honolulu

4. San Jose

5. Seattle

6. Los Angeles

7. Chicago

8. Washington, D.C.

9. Portland

10. Philadelphia

11. Minneapolis

12. San Diego

13. Pittsburgh

14. Miami

15. Denver

16 Milwaukee

17. Buffalo

18. Cincinnati

19. Baltimore

20. Virginia Beach

(You can also see a full list of the best neighborhoods within each city to go trick-or-treating in on Zillow's website)