The Nationalists returned 35 MPs at the last general election in 2017 - the party's second best result in its history by some distance - but well down on the 56 won in 2015. In another Scottish election campaign dominated by the constitution, making gains at the 2019 vote would help boost Nicola Sturgeon's demands for an IndyRef2.
But if the SNP is to strengthen its mandate for a second referendum, experts believe it must win seats from both Labour and the Tories.
Once the base of Tory grandee Sir Michael Forsyth, Stirling was claimed by Labour in 1997 and stayed red until the SNP landslide in 2015. The sprawling constituency - a mixture of towns and villages across a wide central area - was won back for the Conservatives by Stephen Kerr in 2017 with a majority of just 148. The SNP hope the constituency's above average number of pro-Remain voters will unite behind its new candidate, long-running MEP Alyn Smith. Winning back the seat would be a significant result for the Nationalists.
Glasgow North East
This seat on the northern edge of Glasgow takes in much of the old Springburn constituency, the former base of Speaker Michael Martin. It was once prime Labour heartland, but finally went yellow in 2015. Paul Sweeney won it back for Jeremy Corbyn's party in 2017 with a majority of 242. He has been leading an energetic re-election campaign and Labour activists are quietly confident they can hold off the SNP again. Standing for the Nationalists in the seat for third election in a row is experienced campaigner Anne McLaughlin. If Labour can't hold this seat, it's likely to be in for a tough night in Scotland.
This affluent, semi-rural constituency spans central Aberdeenshire and is now a SNP-Tory battleground - despite being held by the Liberals for three decades. Alex Salmond won the seat in 2015, but the former SNP leader's second Westminster career didn't last long. At the 2017 election he lost to Colin Clark - much to the delight of Scottish Tory activists. Clark is standing again and must hope Labour and Lib Dem supporters lend him their vote if he is to see off a strong SNP local campaign, led by candidate Richard Thomson.
Rutherglen and Hamilton West
The ancient royal burgh of Rutherglen stands just on the edge of the Glasgow city boundaries - but has remained proudly detached from its much larger neighbour for more than eight centuries. It was once a Labour stronghold - but like 56 out of 59 constituencies, turned yellow in 2015. Margaret Ferrier won a thumping 9,975 majority then, only to see it wiped out two years later when Ged Killen won the seat back for Labour. Fast forward to 2019 and it's Ferrier v Killen again - with the latter defending a majority of 265.
Losing the Moray constituency was perhaps the single biggest disappointment of the 2017 election for the SNP. Angus Robertson, the party's Westminster leader, was a highly rated Commons performer but that counted for little when he was unseated by Douglas Ross on a swing of 13.6 per cent. Ross is defending a decent majority of 4,159 - but he could be vulnerable if Remain voters in the area opt to vote tactically and back the SNP's new candidate, Laura Mitchell.