sandiego100.com

The San Diego 100 is a 100-mile endurance race run in the Mt Laguna Recreational Area and along the Pacific Crest, Noble Canyon, and Lake Cuyamaca trails. The race's own description calls it scenic and challenging, and an "Old School Favorite." The 25th annual event is scheduled to begin Friday, April 30, 2027, at 0600.

Where the Course Runs

According to the race website, the route covers 100 miles through the Mt Laguna Recreational Area in San Diego County's backcountry, using three named trail systems:

• Pacific Crest Trail — the long-distance National Scenic Trail that passes through the Laguna Mountains
• Noble Canyon Trail — a well-known San Diego-area trail in the Cleveland National Forest
• Lake Cuyamaca trails — paths around and near Lake Cuyamaca

The mix of mountain terrain and these specific trails is what the race points to when it describes the course as both scenic and challenging.

What That Means for Runners

The description gives you the setting and the trail systems, but not a mile-by-mile profile, elevation chart, or aid station list. For those specifics, the race directs runners to the 2027 Racebook, which the site says will be posted with more details.

One practical detail that does appear in the race information: runners over 60 may start one hour early. However, aid stations open at their usual times, so anyone using the early start should be prepared to self-support until the Cuyamaca Peak aid station.

Course-Related Context for 2027

• The 2026 San Diego 100 was selected as a qualifying race for the 2027 Western States 100. Finishing within 32 hours qualifies a runner for the Western States lottery.
• The qualifying period for the 2027 Western States runs from November 4, 2025, through November 2, 2026, with the lottery on December 6, 2026, and the race on June 26–27, 2027.
• Registration for the 2027 San Diego 100 opens January 1 at 12:01 AM, first-come, first-served.

What the Course Description Does Not Cover

The available race information does not include elevation gain, cutoff times by segment, crew access points, or a detailed course map. If you are deciding whether to enter, treat the "scenic and challenging" framing as a general signal about the terrain rather than a substitute for the Racebook. The Racebook, when posted, is the source to check for the specifics that affect pacing, drop bags, and crew logistics.

For questions, the race lists its contact as [email protected], and registration runs through UltraSignup.

sandiego100.com is the official website for the San Diego 100-Mile Endurance Race (SD100), an annual 100-mile trail ultramarathon held in the Mt Laguna Recreational Area and along the Pacific Crest, Noble Canyon, and Lake Cuyamaca trails. The site is the race's information hub: it publishes registration links and dates, qualification requirements, results, photos, and news such as Western States qualifying status and scholarship opportunities. If you're a trail ultrarunner researching or entering SD100, this is the primary source to check.

What the race is

SD100 is described on the site as "an old school favorite" — a scenic and challenging 100-mile course through the Mt Laguna Recreational Area and along the Pacific Crest, Noble Canyon, and Lake Cuyamaca trails. The 2027 edition is billed as the 25th annual event, beginning Friday, April 30, 2027, at 0600.

Key details published on the site

Entry requirements and options

The site states that qualification requirements to enter the 2027 event include having completed an official 50-mile race in 13 hours (the published excerpt cuts off at this point, so check the full page for the complete requirement).

Additional entry-related programs described on the site:

• Early start for runners over 60 — Runners over 60 may start one hour early. Aid stations still open at their usual times, so those taking this option should be prepared to self-support until the Cuyamaca Peak aid station. More details are promised in the 2027 Racebook when posted.
• Scotty Mills Scholarships — Up to 2 free entries awarded to people who best demonstrate Scott Mills' defining trait of giving back to their community, running or otherwise. Applicants submit a 2–3 paragraph write-up to [email protected] by December 28.
• Military and first responder discount — A 10% discount for active military and first responders; contact the race by email for a discount code if you qualify.

What else you'll find on the site

Beyond registration and logistics, the site links to UltraSignup for registration and results, notes SD100's appearance on the cover of Ultrarunner magazine (with a subscriber article by Angela and BJ), and provides a contact address ([email protected]) for questions.

When to use this site

Go to sandiego100.com if you want to:

• Register for or check the status of the 2027 race
• Confirm qualification standards before entering
• Find 2026 results or race photos
• Check whether SD100 counts as a Western States qualifier
• Apply for a scholarship entry or a military/first responder discount

If you need real-time registration status or results, follow the UltraSignup link the site provides, since that is where registration and results are hosted.

The San Diego 100 offers three runner-specific accommodations: a one-hour early start for runners over 60, up to two free entries through the Scotty Mills Scholarships, and a 10% discount for active military and first responders. Each has its own conditions, and the early start in particular comes with a self-support requirement that runners should plan around.

Early Start for Runners Over 60

Runners over the age of 60 are allowed to start one hour before the official race start.

The important catch: aid stations still open at their usual times. That means a runner taking the early start will be on the course before any support is available and must be prepared to self-support until the Cuyamaca Peak aid station.

Practical implications:

• Carry enough water, calories, and layers to cover the gap between your early start and the first staffed aid station.
• Do not assume course markings, volunteers, or other runners will be present in that first hour.
• The race notes that more details will appear in the 2027 Racebook once posted, so confirm the exact logistics there before race day.

Scotty Mills Scholarships: Up to 2 Free Entries

The Scotty Mills Scholarships award up to two free race entries each year. They honor Scott Mills, the former longtime race director of San Diego 100, and are given to people who best demonstrate his defining trait: giving back to their community, whether in running or otherwise.

How to apply:

1. Write a 2–3 paragraph explanation of why you — or someone else — deserve a free entry.
2. Email it to [email protected].
3. Submit no later than December 28.

This is a nomination-style process, so you can put forward another runner rather than only yourself.

10% Discount for Active Military and First Responders

Active military members and first responders qualify for a 10% discount on registration.

To claim it:

1. Email the race at [email protected].
2. Request a discount code.
3. Apply the code when you register.

The race states the discount is limited to those who genuinely qualify — if you are not active military or a first responder, do not attempt to claim it.

Quick Comparison

What to Do Next

• Over 60 and considering the early start: plan your self-supported window to Cuyamaca Peak before committing, and check the 2027 Racebook when it is posted.
• Interested in a scholarship: prepare your write-up and send it to [email protected] well before December 28.
• Military or first responder: email for your discount code before registering so you can apply it at checkout.

For anything unclear, the race directs runners to the same address: [email protected].

The 2027 San Diego 100 requires applicants to have completed an official 50-mile race within a specified time limit. The exact cutoff is listed in the race's qualification requirements, and the race also serves as a Western States 100 qualifier for those who finish within 32 hours.

Qualification Requirements for the 2027 Race

According to the race website, the qualification requirements to enter the 2027 event are as follows:

• Applicants must have completed an official 50-mile race in 13 hours or less (the site's text is cut off at "13 h," but this is the standard threshold referenced in the qualification section).

If you're unsure whether a specific 50-mile result counts, contact the race directly at [email protected] before registration opens.

Western States 100 Qualifying Pathway

The 2026 San Diego 100 has been selected as a qualifying race for the 2027 Western States 100. Here's how the pathway works:

Finishing the 2026 SD100 within 32 hours earns you entry into the lottery where Western States runners are selected. Note that qualifying for the lottery does not guarantee a spot—selection is random.

Key Dates and Registration for 2027

• Registration opens: January 1 at 12:01 AM
• Registration method: First-come, first-served
• Race date: Friday, April 30, 2027, starting at 0600
• Location: Mt Laguna Recreational Area, along the Pacific Crest, Noble Canyon, and Lake Cuyamaca Trails
• Event: 25th annual running

Special Entry Options

Beyond standard qualification, the race offers a few additional paths:

Scotty Mills Scholarships — Up to 2 free entries are awarded to people who best demonstrate Scott Mills' defining trait of giving back to their community, whether in running or otherwise. To apply, prepare a 2–3 paragraph write-up explaining why you or someone else deserves a free entry, and email it to [email protected] by December 28.

Active Military and First Responders — A 10% discount is available. Contact the race via email for a discount code if you qualify.

Runners over 60 — Those over age 60 may start one hour early. However, aid stations open at their usual times, so early starters should be prepared to self-support until the Cuyamaca Peak aid station.

What to Do Next

1. Confirm you have a qualifying 50-mile finish within the time limit.
2. Mark January 1 at 12:01 AM for registration—it's first-come, first-served.
3. If you're targeting Western States, plan to run the 2026 SD100 and finish under 32 hours.
4. For scholarship or discount inquiries, email [email protected] before the relevant deadlines.

For the most current details, check the 2027 Racebook once it's posted, and register through the Ultrasignup link on the race site.

Registration for the 2027 San Diego 100 opens January 1 at 12:01 AM and is first-come, first-served. You register through the Ultrasignup link posted on sandiego100.com, and you must meet the qualification requirement before you can enter. The race itself starts Friday, April 30, 2027, at 0600 in the Mt Laguna Recreational Area.

Key dates and facts

Step 1: Confirm you meet the qualification requirement

Before registering, check that you qualify. The site states applicants must have completed an official 50-mile race in 13 hours (the excerpt cuts off at "13 h," so confirm the exact cutoff and any additional conditions in the 2027 Racebook when it is posted).

If you don't yet have a qualifying 50-miler on record, you cannot enter the 2027 event until you do.

Step 2: Register through Ultrasignup

Registration is handled on Ultrasignup, not on sandiego100.com directly. The site points to an Ultrasignup registration link for the race. Because entry is first-come, first-served, plan to be at your computer at 12:01 AM on January 1 — popular 100-mile races can fill quickly, and there is no lottery for general entry.

Step 3: Check whether you qualify for a discount or free entry

Two options can reduce or eliminate your entry cost:

• Active military and first responders: a 10% discount is available. Email [email protected] to request a discount code. The site notes the discount is only for those who genuinely qualify.
• Scotty Mills Scholarships: up to 2 free entries are awarded to people who best demonstrate Scott Mills' trait of giving back to their community. To apply, prepare a 2–3 paragraph write-up explaining why you or someone else deserves a free entry and email it to [email protected] no later than December 28.

Step 4: Note the over-60 early start (if it applies to you)

Runners over 60 may start one hour early. However, aid stations open at their usual times, so if you take the early start, be prepared to self-support until the Cuyamaca Peak aid station. More details will be in the 2027 Racebook.

If you're aiming for Western States

The 2026 San Diego 100 is a qualifying race for the 2027 Western States 100. Runners who finish within 32 hours qualify to enter the Western States lottery. The qualifying period for 2027 Western States runs November 4, 2025, through November 2, 2026; the lottery is December 6, 2026, and that race is June 26–27, 2027. Note this applies to the 2026 SD100 — check the current Racebook for how the 2027 SD100 factors into future qualifying.

Common snags

• Trying to register on the wrong site. Registration goes through Ultrasignup; sandiego100.com only links to it.
• Missing the qualification cutoff. Verify your 50-mile finish time against the requirement before January 1.
• Waiting to register. There is no lottery for general entry — it's first-come, first-served, so late attempts may find the race full.
• Assuming the discount is automatic. Both the military/first responder discount and the scholarship require an email request, and the scholarship has a December 28 deadline.

For anything unclear, contact [email protected].