You go East of Pinwheel forest near the bridge and you should go North at all the way at the ending. There should be a little entrance and you enter it if you have the National Dex, collected all Gym Badges, and beaten the Elite Four.
To even get to Virizion, you have to catch Cobalion in Mistralton Cave. Virizion, is in Pinwheel Forest.
In pinwheel forest
You can find Virizion in Pinwheel Forest after you have fought Cobalion.
to the north east of pinwheel forest
virizion in pinwheel forest
In Pokemon White, you can find virizion in a clearing in pinwheel forest that isn't accessable untill you catch Cobalion.
In Pinwheel forest, you need to go very deep into the forest, you will see the black shadow thingy that will lead you to Virizions Lair
pinwheel forest find an opening in the gate near the bridge walk through it then it will lead you to virizion
you first have to catch/defeat the legendary pokemon cobalion in mistralion cave you catch virizion in pinwheel forest
You go to the Rumination Field in Pinwheel Forest . It is in the smallest fence opening.
First you have to talk to an old man deep within Mistralton Cave and he will tell you the story about Cobalion, Virizion and Terrakion. Virizion will then appear in a clearing in the Pinwheel forest to the right of the main path.
Virizion is in the Pinwheel Forest. He will not appear until after you defeat or capture Cobalion. Cobalion can be found in Mistralton Cave, east of Route 6. Also, Terrakion can be found in Victory Road, after you capture or defeat Cobalion.