765 ILCS 1070/1
All conveyances, writings or other instruments, whether a deed, mortgage, trust deed, lease, power or letter of attorney, will, bond, contract, agreement, obligation or other instrument of whatsoever kind, nature or character, affecting or relating to the title to real or personal property within this State, or of any power, duty, right or trust thereof or therein, and also all instruments or writings of whatsoever nature, kind or character enforceable in this State, that may have been heretofore or that shall hereafter be executed without this State, by any party thereto, whether a resident of this State or not, to which a seal or scroll to the signature is not affixed, and where the usage or law of the State, district, territory, colony, republic, kingdom, empire, dominion, dependency or other place where such instrument is executed, in force at the time, dispenses with or does not require a seal or scroll to the signature of a party so executing the conveyance, instrument or writing, for its validity as such, are hereby validated, and shall be given the same force and effect as if a seal or scroll had been duly affixed to the signature thereto.
765 ILCS 1070/1