The IRS defines like-kind property as being of the same nature or character, even if they differ in grade or quality. Personal properties of a like class are like-kind properties. However, livestock of different sexes are not like-kind properties. Also, personal property used predominantly in the United States and personal property used predominantly outside the United States are not like-kind properties.
Real properties generally are of like-kind, regardless of whether the properties are improved or unimproved. However, real property in the United States and real property outside the United States are not like-kind properties.
See articles below for more details on like-kind 1031 exchange property.
Alternative and Multiple Properties - Tax-Deferred Exchanges for Apartment Buildings 
An Overview of Like-Kind Property 
Conservation Easements 
Like-Kind Requirements for 1031 Exchanges 
Like-Kind Property - A Look at Easments, Development Rights and Stock of Mutual Ditch, Reservoir and Irrigation Companies 
Receipt of Non-Like-Kind Property is Not Fatal to a Related Party Exchange
Structuring 1031 Exchanges for Farms and Ranches 
Tax Deferred Options for Lease Purchases 
Tenancy-in-Common Revenue Procedure Issued by IRS