Saturday, Oct 9, 2021
This Event Took Place Sat. Oct 9, 2021

Update 10/15/2021

Thanks for looking. The 2022 event is on Oct 8th. (10/8/2022). Registration opens 1/1/22.

See you next year.

Course Description

WELCOME. Race Headquarters is in the parking lot at the north end of scenic Lake Merced lake at the foot of Sunset Boulevard in San Francisco, California. This is where you will park, check in, get your number, and receive aid.

It's a mostly flat, certified, 4.5-mile loop on either an asphalt path or groomed dirt shoulder around the lake. It's possible to run on the groomed shoulder path about 90% of the loop. There is approximately 100' of elevation gain and loss per loop.

With two exceptions, you will stay on the paved path that circles the lake. There are two spots approximately 0.5 miles after the start of the first lap where you will go straight and not follow the longer paved route. We will try to mark this on race day and will announce it prior to the start.

Runners will enjoy one aid station per loop fully stocked with water, electrolytes, and a wide selection of foods. You will also have access to your vehicle and are allowed to set up supplies near the aid station. A second water fountain is located about half way through the loop.

Start and Finish lines

New this year, there are two turn-around points on the course. The parking lot at the foot of Sunset Blvd. is "Race Headquarters." This is where you will park, check in, set up your supplies, get aid, and have your completed laps counted. It is now the finish line for the 50 km. and 50 mile events.

The start line for all races is a 0.52 mile walk from this area, and we will leave about 6:15. Note that it will be dark at this time of the year.

The first running loop for everyone is 3.95 miles followed by multiple 4.47 mile loops.

The first finishing decision is for the 50 km. At 0.16 mi. after you finish your sixth full lap (mile 30.8) you can turn around and run back towards the timing tent to finish there. Note that this year you will not receive an official 50 km. split time en-route to your 50 mi. event unless you notify us that you are attempting to set a USATF record.

The next finishing distance is 50 miles. So that you can finish back at Race HQ, after your 11th full lap you'll run out 0.645 miles to a turn-around point then run back to the finish line at Race HQ. Both turn-around points will be clearly marked with chalk and a small sign. You'll have time to get to know these locations, but ask us as you go by if you are confused.


Runners will be allowed to choose their distance during the race, but a runner can only be a finisher at one distance. Once reaching the 50 km turn-around point, a runner must decide whether to continue or stop. If the runner turns and stops at 50 km., he/she is a finisher in that race and his/her tag will be pulled. Choosing to go beyond the 50 km. turn-around point makes the runner an entrant and competitor in the 50 mile event. You cannot continue past one distance and decide later that you want to be scored in the earlier distance. If you have questions, please ask.

There is essentially no cutoff for 50 km. as long as you can keep moving.

50 mile runners have one cutoff to meet based on a 15 min./mi. finishing pace:

They should finish their 10th lap (44.2 miles) by 11 hours, i.e. by 5:30 p.m., into the race.

Lighting needs

Civil sunrise is at 6:48 am that day. The start is at 6:30, so you will be running in the dark for part of the first lap. Even though most of the route is on a wide, public path, you might want to carry a small light at the start. You can drop your light near the timing tent.

Civil sunset is at 7:02 pm that day.


Note that this year we have decided to have the 50 km finish in front of the timing tent. This requires you to turn around 0.016 mi. after your sixth full lap. A sign will be there to indicate where to turn. If it is your First Ultra please reach out to RD or Mr. Rao's mentor friend RD for a 20% discount code.

All finishers will receive a custom Ruth Anderson Memorial Patch.

Be prepared to show proof of vaccination at number pick up.

If you think you might set a USATF age-group record, please let us know in advance so we can be sure to have the appropriate timing in place.

For more information on Ruth see

Local time: 1:26 PM


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