Cometary orbits appear to be split into two groups:

But First, quick look at the solar system

"Short-Period Comets"

• Orbits are less than 200 years long
• Orbits confined to plane of solar system
• Aphelion (furthest point from sun) appear to be in "Kuiper Belt"
• Example: Halley's Comet - orbit takes 76 years.

"Long-period comets"

• Orbits much greater than 200 years long
• Orbits not confined to plane - can come from anywhere
• Aphelion appears to be in "Oort Cloud"
• Example: Hyakutake - orbit did take roughly 8000 years, but now 14000 years due to Jupiter.