Beds Police stated: "Officers remain at the scene following a road traffic collision on the northbound carriageway of the A1 just past Junction 10, which happened last night (Friday) between 9.45pm and 10pm.
"There are closures between Baldock services station and Biggleswade.
"One woman was pronounced dead at the scene. While she has not been formally identified, her next of kin are aware.
"If anyone has any information, please call 101 or visit our online reporting tool and quote reference Op Firbeck.
"Thank you for your patience."