Exhibit 24
POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Patricia Diaz Dennis    
Patricia Diaz Dennis







POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Dan O. Dinges     
Dan O. Dinges





POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ John G. Drosdick     
John G. Drosdick






POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ John J. Engel         
John J. Engel







POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Murry S. Gerber     
Murry S. Gerber






POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint David B. Burritt and Colleen M. Darragh or either one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Mario Longhi     
Mario Longhi






POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Glenda G. McNeal     
Glenda G. McNeal







POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Robert J. Stevens    
Robert J. Stevens





POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ David S. Sutherland     
David S. Sutherland







POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS:
That the undersigned does hereby make, constitute and appoint Mario Longhi, David B. Burritt and Colleen M. Darragh or any one of them, my true and lawful attorneys-in-fact to sign and execute for me and on my behalf United States Steel Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015 to be filed with the Securities and Exchange Commission, and any and all amendments to such report to be filed with the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934, as amended, in such form as they or any one or more of them may approve, and to do any and all other acts which said attorneys-in-fact may deem necessary or desirable to enable United States Steel Corporation to comply with said Act and the rules and regulations thereunder.
IN WITNESS WHEREOF, I have hereunto set my hand this 29th day of February, 2016.

/s/ Patricia A. Tracey     
Patricia A. Tracey