I thought this was common knowledge.  I guess I thought everyone knew this since the archdiocese I live in has had a woman chancellor for quite some time.

Actually, what surprised me was that there are so few women chancellors in the United States.  I thought it was more widespread.  When I had first learned that the archdiocese had a woman chancellor, I was shocked at this, but found that the chancery is merely the diocesan record keeper so the position is not necessarily a position that would intrinsically require an ordained priest.

Canon 372 §1. In every Curia the Bishop shall constitute a chancellor, who must be a priest, whose principal responsibility is to maintain the acts of the Curia in the archive, to arrange them in chronological order, and to make an index chart of them.
§2. Necessity obtaining, he can be given a helper, whose name is vice-chancellor or vice-tabulary.
§3. A chancellor is by that fact a notary.

Can. 482 §1. In every curia a chancellor is to be appointed whose principal function, unless particular law establishes otherwise, is to take care that acts of the curia are gathered, arranged, and safeguarded in the archive of the curia.
§2. If it seems necessary, the chancellor can be given an assistant whose title is to be vice-chancellor.
§3. By reason of being chancellor and vice-chancellor they are notaries and secretaries of the curia.

In a diocese, he is the chief representative of the bishop, especially in the administration of temporal affairs. His role varies in different dioceses but may include the hearing of applications for faculties and dispensations, the preservation and arrangement of the diocesan docuмents, and in general acting as the bishop's secretary.