Reigning world champion Rovanpera led from the rally's start on Thursday in Riga and never looked like being pipped to the post as the four-day race reached its end in Liepaja.
"It has been a great weekend... It is cool to have the first win here, Latvia is an important place for me," said Rovanpera, who started his first-ever rally in the Baltic country more than 10 years ago as a 12-year-old.
The Toyota driver finished nearly 40 seconds ahead of France's eight-time champion Sebastien Ogier, also of Toyota, with Estonian Ott Tanak of Hyundai a further 25.3sec behind.
Tanak climbed to second in the overall drivers' championship with his third-place finish, and now sits just eight points adrift of his Hyundai team-mate Neuville.
Results:
1. Kalle Rovanpera/Jonne Halttunen (FIN/Toyota) 2:31:47.6, 2. Sebastien Ogier/Vincent Landais (FRA/Toyota) at 39.2, 3. Ott Tanak/Martin Jarveoja (EST/Hyundai) 1:04.5, 4. Adrien Fourmaux/Alexandre Coria (FRA/M-Sport Ford) 1:31.5, 5. Elfyn Evans/Scott Martin (GBR/Toyota) 1:42.7, 6. Takamoto Katsuta/Aaron Johnston (JPN-IRL/Toyota) 2:07.0, 7. Martins Sesks/Renars Francis (LVA/Ford M-Sport) 2:45.4 8. Thierry Neuville/Martijn Wydaeghe (BEL/Hyundai) 2:46.4, 9. Gregoire Munster/Louis Louka (NED-BEL/Ford) 5:23.1, 10. Esapekka Lappi/Janne Ferm (FIN/Hyundai) 5:12.4
Special stage winners
Kalle Rovanpera (SS1, SS2, SS6, SS7, SS8, SS9, SS10, SS12, SS13, SS14, SS16), Ott Tanak (SS11, SS18, SS19, SS20), Sebastien Ogier (SS5, S15, SS17), Martins Sesks (SS3, SS4)
Championship standings
1. Thierry Neuville/Martijn Wydaeghe (BEL/Hyundai) 145 points, 2. Ott Tanak/Martin Jarveoja (EST/Hyundai) 137, 3. Elfyn Evans/Scott Martin (GBR/Toyota) 132, 4. Sebastien Ogier/Vincent Landais (FRA/Toyota) 117, 5. Adrien Fourmaux/Alexandre Coria (FRA/M-Sport Ford) 101, 6. Kalle Rovanpera/Jonne Halttunen (FIN/Toyota) 86
