Okla. Stat. tit. 58, § 58-5: Venue of probate acts

The district court in and for the county of proper venue has

exclusive jurisdiction to prove a will or to grant letters

testamentary or of administration. Proper venue for hearing in such

actions shall be determined as follows:

1. If the decedent died as a resident of this state, in the

county of which the decedent was a resident at the time of his or

her death, regardless of where the decedent died;

2. If the decedent died while not a resident of this state:

a. first, in the county of this state in which the

decedent died, leaving an estate therein,

b. second, in any county of this state in which any part

of the estate of the deceased may be, where the

decedent

(1) died out of this state, or

(2) died within this state but did not leave an

estate in the county in which the decedent died,

and

c. third, in the county in which the decedent died,

leaving no estate in this state; or

3. In all cases of administration of estates of deceased

persons in this state where final decrees have been entered prior to

the effective date of this act, and for which the final decrees are

or may be defective or invalid for lack of jurisdiction because the

administration was in a county other than the county of proper venue

as prescribed by this section, such final decrees shall be deemed

valid; provided, however, the provisions of this paragraph:

a. shall not apply to any case where an action is

instituted and maintained to modify or vacate the

final decree within one (1) year of the effective date

of this act, and

b. shall not bar the claim of a person claiming an

interest in a decedent's estate if the person did not

receive notice of the probate or estate

administration, actual or constructive, as required by

this title.