This Count von Moltke is Danish. A terse genealogical sketch is here. They married in 1907. A New York Times article about his diplomatic posting that mentions their marriage is here.
From the USA Library of Congress Bain Collection; spots throughout image and old Bain copyright mark to the right of Countess Moltke's hat removed with Photoshop by gogm.
Countess Cornelia wears a pre-war day dress with a columnar line highlighted by ornamental buttons on the middle bodice and skirt as well as more buttons on her sleeves.
Keywords: 1914, Molltke family, Countess, hat, high neckline, collar, lace, elbow length sleeves buttons, waist band, natural waistline, gloves