Consideration received for the granting of an easement constitutes the proceeds from the sale of an interest in real property and should be applied as a reduction of the cost or other basis of the portion of the land subject to the easement. (Rev. Rul. 68-291 clarifying Rev. Rul. 59-121) If it is impossible or impractical to separate the basis of the part of the property on which the easement is granted, the basis of the whole property is reduced by the amount received. Any amount received that is more than the basis to be reduced is a taxable gain. (IRS Pub 544, Pg 3)

CAUTION: If the easement is for a specific period of time, then it is generally treated as rental income. (Wineberg, William, (1961) TC Memo 1961-336), but see GCM 35492 (9/73) for a different outcome).