Aintree Course Guide: Grand National Course vs Mildmay Course, and the Fences

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By The Guv'nor · Last updated October 2026

My Aintree course guide in one line: there are two chase courses. The Grand National course is the big left-handed loop with 16 famous fences, used for the National, Topham, Foxhunters', Becher and Grand Sefton. The Mildmay is a much tighter track with standard birch fences, used for every other Aintree chase.

The betting question is whether form on one tells you anything about the other, so I checked every Grand National runner's Aintree record since 2013.

Aintree course guide: the two chase courses

Fence details are from The Jockey Club's Grand National fences page; field sizes are my count from Betfair's 2025/26 price files.

There's a hurdles track too, but no stalls, so unlike the Flat tracks in my draw bias guide there's no draw to worry about. Every other track is in my UK and Irish racecourses list.

The Grand National fences, one by one

The National is 30 jumps: 16 fences on the first circuit and 14 of them again on the second. The Chair and the Water Jump are only jumped once. Heights are The Jockey Club's, with fence 11 as cut for 2024.

How the fences have changed

After the 2012 race the inner frame of every fence was changed from timber to flexible plastic or natural birch, still dressed in spruce. Then, in October 2023, The Jockey Club announced a standing start for every race over these fences and, for the 2024 National, moved the first fence closer to the start, lowered fence 11 and fitted foam and rubber toe boards to every fence. The National field was also cut from 40 to 34. What that did to the trends is on my Grand National trends page.

After the last there's a run-in of nearly 500 yards (about 450 metres), with a dog-leg called the Elbow, and plenty of Nationals have changed hands on it.

The Mildmay course: a sharp park track

The Mildmay opened in December 1953 and was named after Lord Mildmay, the champion amateur rider who wanted a "nursery" course of smaller National-style fences. The spruce went in 1975, replaced by standard birch, and the layout changed again in 1990, so today it's a normal, fairly tight left-handed park track.

At the Festival it hosts the Grade 1 chases (the Bowl, Melling, Manifesto, Mildmay Novices' and Maghull) plus the Red Rum and Freebooter handicaps, and it takes every chase at the smaller fixtures, such as the Old Roan Chase in the autumn.

Two things stand out for punters. The fields are small: 7.4 runners a race in 2025/26, against 23 over the National fences. And a tight track with normal birch is a different question from four miles over spruce.

Does Mildmay form transfer to the National course?

The old line is that a horse who has "handled Aintree" has an edge. So I sorted all 495 runners in the 13 Nationals from 2013 to 2026 by what they'd done at Aintree before the race.

If I am honest, not much. Mildmay-only horses made the top four 9.1% of the time against 10.5% for the whole field, and they got round less often (40.3% against 44.4%). Horses that had already jumped the big fences finished a bit more often (47.0%), but their top-four rate is close to par.

Narrow it down to horses that had won a chase on the Mildmay but never run over the National fences and it gets worse: 26 runners, 9 finished (34.6%), and the only one to make the first four was Corach Rambler, who won in 2023 after winning a novice handicap on the Mildmay in October 2021.

Meanwhile, five of the 13 winners had never run at Aintree, including Noble Yeats (50/1, 2022) and Nick Rockett (33/1, 2025).

Aintree going and stamina in April

Aintree waters to keep the ground safe, and The Jockey Club said in 2023 it had spent more than £400,000 improving the watering system, with more pop-up irrigation to come. The 2024 move to an earlier start time was partly about ground management too. In practice, most recent Nationals have been run on good to soft.

Seven of the ten were run on ground described as good to soft, and all were won in under 9m 16s. The three soft or heavy years were the three slowest, all over 9m 27s, and heavy ground in 2018 had the fewest finishers (12 of 38). But 2024, on soft, had the most (21 of 32), so going alone doesn't decide how many get round.

Aintree can also report different going for each course. In 2013, 2014 and 2015 the official going was good, with the National course given separately as good to soft, good in places. Check which course a going report refers to; my going explained guide explains the terms.

At 4m2½f (about 6,900 metres), the longest jumps trip in the UK, the National is about seeing out the trip, not handling tight bends.

The Becher Chase and other National trials at Aintree

Before April, the big date over the National fences is Becher Chase Day on Saturday 5 December 2026, when the Grand Sefton returns to the card after five seasons in early November. The Becher is a handicap over 3m1f188y and the Grand Sefton is run over 2m5f19y. My big races 2026/27 calendar has the build-up.

How have Becher runners done in the National the following April? From the same 2013 to 2026 data, 58 National runners had run in that season's Becher. Two won (Pineau De Re, who fell in the 2013 Becher, and One For Arthur, fifth in the 2016 running), six made the top four and 30 finished (51.7%), against 44.4% for the whole field. Slightly better at getting round, on a small sample, and all six top-four finishes came between 2014 and 2019.

Fourteen National runners had run in that season's Grand Sefton: none won, one made the top four (Johnnywho, fourth in 2026 after finishing fifth in the November 2025 running) and six finished.

The Foxhunters' (2m5f, for hunter chasers, on Thursday 8 April 2027) and the Topham (2m5f handicap, Friday 9 April 2027) use the National fences during the Festival itself, so they aren't trials for that year's race. My Grand National preview covers the road to Aintree.

How I read Aintree form

Look, I'm essentially a statistics and maths geek, so the romance of "he loves Aintree" doesn't move me on its own. What moves me is price. If a horse's Mildmay win has knocked a few points off its National odds, the table above suggests I'm probably paying for something that doesn't carry across.

A 34-runner handicap is where outsiders and each-way value live, which is how I like to bet anyway. Even when they only place, we make more profit than an odds-on shot winning. I stake in points (1pt can be £5 on a £100 bank), I never go all in on a feeling, and if I'm unsure about one I skip it. With fewer than half the field getting round most years, understanding that losers are a thing is the key to being a winner longer term. Trust the process.

Aintree course FAQs

How many fences are in the Grand National?

There are 16 fences on the course and 30 jumps in the race. Fourteen fences are jumped twice; The Chair and the Water Jump are only jumped on the first circuit.

What is the Mildmay course at Aintree?

Aintree's second chase course: a tighter left-handed track with standard birch fences, used for every Aintree chase not run over the National fences.

What are the names of the Grand National fences?

The named ones are Westhead (3 and 19), Becher's Brook (6 and 22), Foinavon (7 and 23), the Canal Turn (8 and 24), Valentine's Brook (9 and 25), Booth (12 and 28), The Chair (15) and the Water Jump (16).

More in this guide

• UK and Irish racecourses: every track by direction and shape
• Cheltenham course guide: Old Course vs New Course
• Grand National trends since 2013
• Grand National 2027 preview
• Horse racing going explained