Petroleum Engineering tops the list with a mid-career salary of $187.3K in the US, followed by Operations Research & Industrial Engineering at $170.4K. This is likely due to the high demand and technical expertise required in the oil and gas industry, combined with the lucrative nature of the field. Operations Research & Industrial Engineering follows at $170.4K, as these roles are critical for optimizing processes and improving efficiency in various industries, making them highly valuable and well-compensated.