Here are the 10 biggest road races in the United States, along with registration information for each. (Based on number of finishers in 2016; compiled by Running USA)

1. Finishers in 2016: 56,993 / Atlanta, Georgia
Finishers in 2016: 56,993
Date of 2018 race: Saturday, April 7
Running Shoes - Gear
Registration: Closed for 2017

2. Date of 2018 race: Monday, April 16 / Peachtree Road Race
Finishers in 2016: 51,267
Date of 2017 race: Sunday, November 5
Distance: 26.2 miles
Registration: Closed for 2017; spots in charity program are available

3. Bolder Boulder / Boulder, Colorado
Finishers in 2016: 44,671
Registration typically opens in September for qualified runners
Running Shoes - Gear
Registration: Open now

4. Health - Injuries / Spokane, Washington
Finishers in 2016: 28,009
How to Better Pace a Marathon Based on Effort
Nutrition - Weight Loss
Registration: Open now

5. Chicago Marathon / Chicago, Illinois
Broad Street Run
Estimate Your Marathon Time Based On Your 10K PR
Distance: 26.2 miles
Registration: Closed for 2017; spots in charity program and international tour group program are available

6. Broad Street Run / Philadelphia, Pennsylvania
Finishers in 2016: 34,237
How to Better Pace a Marathon Based on Effort
Distance: 10 miles
Registration: Closed for 2017

7. Bay to Breakers / San Francisco, California
Finishers in 2016: 28,009
Virtual Races With the Best Bling
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Registration: Open now

8. Brooklyn Half Marathon / Brooklyn, New York
Your Marathon Packing Checklist
Distance: 10 miles
Date of 2017 race: Monday, May 29
Registration: Closed for 2017; some charity spots available

9. Running Shoes - Gear / Joaquin Lara/Atlanta Track Club
Finishers in 2016: 26,804
Date of 2018 race: Saturday, April 7
Running Shoes - Gear
Registration: Open now

10. Boston Marathon / Boston, Massachusetts
Health - Injuries
Date of 2018 race: Monday, April 16
Distance: 26.2 miles
Registration: Distance: 13.1 miles