During the first act of the game, a dragon mound opens near Witchmist Grove- specifically, during your time with the Graybeards up in High Hrothgar. Unlike in many other cases, this dragon doesn’t always leave the area completely- if you head over to Witchmist Grove before going after the Horn of Jurgen Windcaller, you can spot it in the air over Witchmist Grove itself. This is an excellent opportunity to kill it- or to get horribly murdered by the one kind of creature that manages to actually be more dangerous than dragons- giants. It is not, however, impossible.
The thing about Witchmist Grove is that it’s located between two giant camps. Generally if you approach the area from the East, you can pass between the camps as you approach the dragon circling overhead. This lets you get the attention of the dragon- which will then get the attention of one or more giants and at least one mammoth in the process. While it can be helpful, this is also very dangerous.
When the dragon stoops to belch flame, it will frequently hurt a giant or mammoth, which gets them to attack the dragon in turn. This is all well and good, since they’ll distract the dragon and deal extra damage to it. The problem comes in afterwards- once the dragon dies, since you (and your follower) were in sight range of any giants who contributed, they’ll then turn and attack you. Fortunately, the roof of the Witchmist Grove witch’s house is unreachable by anyone who doesn’t jump- namely anyone not you. This lets you perch atop it and kill things with impunity- if you use a bow or spells. Slow, but rewarding.
Regardless of that, the dragon is a simple firebreather. The real challenge is handling it if you don’t get help from the local giants and mammoths. There is no tower, nor really any good structure to take shelter in and snipe the dragon from. You can sort of use the house, but that means facing the witch first, not the best idea when you’re already dealing with a dragon. Additionally, the house has windows and such, so it’s not as easy to get out of breath weapon reach, and just to make things worse, the dragon doesn’t like landing on or near the house, further complicating things.
Your best bet on that is to try and take advantage of the grove itself, darting from tree to tree to keep a trunk between you and the dragon at all times. This renders the fight into a contest of endurance, and while you can hide behind trees to escape damage, the dragon cannot and will therefore lose the fight.