Recent advances in brain imaging allow producing large amounts of 3-D volumetric data from which morphometry data is reconstructed and measured. Fine detailed structural morphometry of individual neurons, including somata, dendrites, axons, and synaptic connectivity based on digitally reconstructed neurons, is essential for cataloging neuron types and their connectivity. To produce quality morphometry at large scale, it is highly desirable but extremely challenging to efficiently handle petabyte-scale high-resolution whole brain imaging database. Here, we developed MorphoHub to address this challenge by optimizing both the data and workflow management. In particular, this work presents a multi-level method to produce high quality somatic, dendritic, axonal, and potential synaptic morphometry. Our method also boosts data sharing and remote collaborative validation. We applied MorphoHub to a petabyte application dataset involving 62 whole mouse brains, and identified 50,233 somata of individual neurons, profiled the dendrites of 11,322 neurons, reconstructed the full 3-D morphology of 1,050 neurons including their dendrites and full axons, and detected 1.9 million putative synaptic sites derived from axonal boutons. Analysis and simulation of these data indicate the promise of this approach for modern large-scale morphology applications.necessary to analyze synaptic patterns in a neuron's arborization, while whole-brain scale is essential to delineate long projecting axonal arbors 8 . As a result, even for the mouse brain, a widely used model system of mammalian brains, a typical 3-D brain-image dataset will have tens of teravoxels in volume 9,10 . On the other hand, neurons have a very complicated tree-like shape, and are often labelled and visualized sparsely using chemical 11,12 , transgenic 13 or viral approaches 14,15 . The number of morphologically distinguishable neurons per brain is often limited. Therefore, to understand the vast complexity and variation of neurons, it is crucial to obtain a large collection of brain image datasets 16,17 . As each voxel is often stored as one or more bytes, the multimorphometry problem arises as a petabyte-computing challenge, and as a paramount task for current bioimage informatics applications and technologies [18][19][20][21] .There is a long history of reconstructing individual neurons' morphology with image analysis 22,23 . Subneuronal structures including somata, spines and boutons have also been segmented and analyzed from images 5,24-28 . This is a challenge of high community interest. A number of algorithms have been examined and compared against each other in public initiatives, e.g. DIADEM 29 or in the global collaborative BigNeuron initiative 30 . However, most existing methods are applicable only to smaller image datasets and partial neuronal structures. For individual mammalian brain datasets, technologies that can handle teravoxels of image volume to trace millimeters long neurite fibers emerged only recently, including TeraFly 31 , UltraTracer 32 , BigDataV...