Aeronautical Information Manual (AIM), page 159
12/10/15 AIM
Section 3. Class G Airspace
3-3-1. General 3-3-3. IFR Requirements
Class G airspace (uncontrolled) is that portion of
airspace that has not been designated as Class A, a. Title 14 CFR specifies the pilot and aircraft
Class B, Class C, Class D, or Class E airspace. equipment requirements for IFR flight. Pilots are
reminded that in addition to altitude or flight level
requirements, 14 CFR Section 91.177 includes a
3-3-2. VFR Requirements
requirement to remain at least 1,000 feet (2,000 feet
Rules governing VFR flight have been adopted to in designated mountainous terrain) above the highest
assist the pilot in meeting the responsibility to see and obstacle within a horizontal distance of 4 nautical
avoid other aircraft. Minimum flight visibility and miles from the course to be flown.
distance from clouds required for VFR flight are
contained in 14 CFR Section 91.155. b. IFR Altitudes.
(See TBL 3-1-1.) (See TBL 3-3-1.)
TBL 3-3-1
IFR Altitudes
Class G Airspace
If your magnetic course And you are below
(ground track) is: 18,000 feet MSL, fly:
0 to 179 Odd thousands MSL, (3,000; 5,000; 7,000, etc.)
180 to 359 Even thousands MSL, (2,000; 4,000; 6,000, etc.)
Class G Airspace 3-3-1
Page 159 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures