Inclinometers with a parallel dipole line (PDL) trap system are provided. In one aspect, an inclinometer includes: a PDL trap having a pair of dipole line magnets, a transparent tube in between the dipole line magnets, and a diamagnetic object within the transparent tube, wherein the diamagnetic object is levitating in between the dipole line magnets; and a sensing system for determining a position z of the diamagnetic object in the PDL trap and for determining an inclination angle θ using the position z of the diamagnetic object in the PDL trap. Techniques to detect the diamagnetic object position using optical, capacitive and manual methods are described. A method for determining an inclination angle θ using the present inclinometers is also provided.