Sen. Bernie Sanders’s road to a comeback in the Democratic primary once again runs through Michigan. In 2016, Sanders overcame massive polling deficits and less than 1 in 100 odds to score a shocking win in the Michigan primary, showing there was still life in his campaign despite former Secretary of State Hillary Clinton’s significant delegate lead.

Sanders is now hoping the Wolverine State can do the same for him four years later. Michigan is Sanders’s most important upcoming state for a few reasons. It is big enough (125 pledged delegates) to present him with an opportunity to cut his delegate deficit. It also leans enough toward former Vice President Joe Biden that another Sanders upset there would sow doubt about whether Biden is really as strong as he looks. Finally, Michigan has the benefit of voting now. Well over half of the pledged delegates will have been awarded by the end of this month, meaning that Sanders can’t afford for his comeback to start in April — if it’s going to happen, it needs to start soon.

According to the FiveThirtyEight forecast as of 9 p.m. Eastern on March 8, Biden had a 3 in 4 (77 percent) chance of winning Michigan, while Sanders had a 1 in 4 (23 percent) chance. On average, Biden is forecasted to receive 51 percent of the statewide vote in Michigan, and Sanders is forecasted to receive 42 percent. But those results will likely not be consistent across all corners of the state. We’re forecasting that 11 of Michigan’s 14 congressional districts will be tighter than that — a welcome development for Sanders, given that 82 of Michigan’s pledged delegates are awarded on the district level and he’s overperfoming in several of them.

So let’s take a look at Sanders’s and Biden’s relative strength in each Michigan congressional district (this is in the average scenario of a 51-42 Biden statewide win):

Most districts are close, but Biden dominates in Detroit Average forecasted vote share for the top two Democratic presidential candidates in Michigan congressional districts, according to the FiveThirtyEight model as of 9 p.m. on March 8 District Biden Sanders MI-01 50% 43% MI-02 48 46 MI-03 49 44 MI-04 49 44 MI-05 52 41 MI-06 50 43 MI-07 49 44 MI-08 48 46 MI-09 49 44 MI-10 48 45 MI-11 47 46 MI-12 49 44 MI-13 60 33 MI-14 61 32 State 51 42

The 13th District and 14th District immediately jump out as the two best districts in the state for Biden. Not coincidentally, these two Detroit-based districts were also — by far — Clinton’s strongest districts in Michigan in 2016, as she crushed Sanders in each by more than 30 percentage points. The fact that both districts are majority black bodes well for Biden just as it did for Clinton; according to exit polls, Biden got 58 percent of the black vote in the median state on Super Tuesday, while Sanders got just 17 percent. In our average forecast, Biden gets 60-61 percent of the vote in these districts, while Sanders gets 32-33 percent. So on election night, if Sanders is leading statewide but the City of Detroit has yet to report, don’t jump to any conclusions — this is Biden’s base.

On the other hand, most other districts in the state figure to be close — none more so than the 11th District (which covers certain northern and western Detroit suburbs like Troy and Livonia), where we are forecasting Biden to get an average of 47 percent and Sanders to get an average of 46 percent. We also expect Sanders to overperform his statewide vote share in the 8th District (which runs from Lansing to the Detroit suburb of Rochester). The 8th and 11th districts have a lot in common, too, besides their expected affinity for Sanders: They are Michigan’s two wealthiest and most college-educated districts, and Democrats flipped both these seats in the 2018 elections.

Sanders is also forecasted to hit 46 percent and almost tie Biden in the 2nd District, which includes some suburbs of Grand Rapids and much of the Lake Michigan shoreline. The district was notably one of Sanders’s best districts back in 2016 (he beat Clinton by more than 20 points). And in the 10th District, a heavily non-college-educated white district covering Michigan’s “Thumb,” our forecast predicts Biden to get 48 percent and Sanders to get 45 percent. If Sanders is going to overperform on Tuesday, these four districts — the 2nd, 8th, 10th and 11th — will probably be leading indicators.

Finally, if it’s a bellwether district you’re after, look no further than the 5th District. Racially, this Flint- and Saginaw-based district looks like Michigan as a whole, although it is also one of the least wealthy and college-educated districts in the state. We’re forecasting Biden to get an average of 52 percent here and Sanders to get an average of 41 percent, which closely matches their expected statewide performance. Sanders winning here on election night could be the first sign that a statewide upset is brewing.

Of course, there’s also a lot of uncertainty as we move into Tuesday, not least because we don’t have many recent polls of Michigan to help us understand how close this race is. But as results come in, keep in mind some of these congressional-district benchmarks, as they can help you judge who might be on pace to win statewide.